Document And Entity Information (USD $) In Billions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Jan. 30, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Entity Registrant Name	SEI INVESTMENTS CO
Entity Central Index Key	0000350894
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	SEIC
Amendment Flag	false
Entity Common Stock, Shares Outstanding		166,832,044
Entity Public Float			$ 4.3
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current Assets:
Cash and cash equivalents	$ 667,446	$ 578,273
Restricted cash	5,801	5,500
Receivables from regulated investment companies	48,393	39,364
Receivables, net of allowance for doubtful accounts of $784 and $651	194,419	186,664
Securities owned	21,175	21,133
Other current assets	18,193	16,166
Total Current Assets	955,427	847,100
Property and Equipment, net of accumulated depreciation of $241,295 and $220,064	125,535	118,995
Capitalized Software, net of accumulated amortization of $218,514 and $180,062	309,040	312,615
Investments Available for Sale	77,609	83,323
Investments in Affiliated Funds, at fair value	4,523	4,849
Investment in Unconsolidated Affiliates	54,290	61,370
Other Assets, net	16,451	10,917
Total Assets	1,542,875	1,439,169
Current Liabilities:
Accounts payable	10,588	16,235
Accrued liabilities	207,429	188,123
Deferred income taxes, net	1,414	1,653
Deferred revenue	1,749	1,977
Total Current Liabilities	221,180	207,988
Deferred Income Taxes	63,755	66,572
Other Long-term Liabilities	10,327	8,607
Total Liabilities	295,262	283,167
Commitments and Contingencies
SEI Investments shareholders' equity:
Series Preferred stock, $.05 par value, 50 shares authorized; no shares issued and outstanding	0	0
Common stock, $.01 par value, 750,000 shares authorized; 166,688 and 169,242 shares issued and outstanding	1,667	1,692
Capital in excess of par value	834,615	721,219
Retained earnings	420,226	431,604
Accumulated other comprehensive (loss) income, net	(8,895)	1,487
Total Shareholders' Equity	1,247,613	1,156,002
Total Liabilities and Equity	$ 1,542,875	$ 1,439,169

Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current Assets:
Receivables, allowance for doubtful accounts	$ 784	$ 651
Property and Equipment, accumulated depreciation	241,295	220,064
Capitalized Software, accumulated amortization	$ 218,514	$ 180,062
Equity:
Series Preferred stock, par value	$ 0.05	$ 0.05
Series Preferred stock, shares authorized	50,000	50,000
Series Preferred stock, shares issued	0	0
Series Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	166,688,000	169,242,000
Common stock, shares outstanding	166,668,000	169,242,000

Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Asset management, administration and distribution fees	$ 948,932	$ 831,720	$ 723,630
Information processing and software servicing fees	285,463	261,691	236,190
Transaction-based and trade execution fees	31,610	32,721	32,702
Total revenues	1,266,005	1,126,132	992,522
Expenses:
Subadvisory, distribution and other asset management costs	149,791	121,989	106,048
Software royalties and other information processing costs	33,522	31,255	26,722
Brokerage commissions	23,002	24,649	23,889
Compensation, benefits and other personnel	376,873	357,453	335,296
Stock-based compensation	13,463	37,865	15,736
Consulting, outsourcing and professional fees	136,818	131,399	109,828
Data processing and computer related	52,512	51,401	46,617
Facilities, supplies and other costs	66,113	64,613	60,976
Amortization	38,679	34,602	33,258
Depreciation	22,448	22,497	22,586
Total expenses	913,221	877,723	780,956
Income from operations	352,784	248,409	211,566
Net gain from investments	614	659	14,067
Interest and dividend income	3,354	3,248	5,696
Interest expense	(458)	(535)	(504)
Equity in earnings of unconsolidated affiliates	127,786	118,076	98,671
Gain on sale of subsidiary	5,582	22,112	0
Other income	0	43,429	0
Income before income taxes	489,662	435,398	329,496
Income taxes	170,949	146,924	121,462
Net income	318,713	288,474	208,034
Less: Net income attributable to the noncontrolling interest	0	(350)	(1,186)
Net income attributable to SEI Investments Company	$ 318,713	$ 288,124	$ 206,848
Basic earnings per common share	$ 1.89	$ 1.68	$ 1.19
Shares used to compute basic earnings per share	168,246	171,561	174,295
Diluted earnings per common share	$ 1.85	$ 1.64	$ 1.18
Shares used to compute diluted earnings per share	172,565	175,718	175,872
Dividends declared per common share	$ 0.46	$ 0.42	$ 0.63

Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 318,713	$ 288,474	$ 208,034
Other comprehensive (loss) gain, net of tax:
Foreign currency translation adjustments	(10,189)	(3,760)	5,904
Unrealized holding (loss) gain on investments:
Unrealized holding gains (losses) during the period, net of income taxes of $(592), $(954) and $86	441	(1,149)	341
Less: reclassification adjustment for gains realized in net income, net of income taxes of $319, $170 and $50	(634)	(294)	(86)
Total other comprehensive (loss) gain, net of taxes	(10,382)	(5,203)	6,159
Comprehensive income	308,331	283,271	214,193
Less: Comprehensive loss (income) attributable to noncontrolling interest	0	101	(3,006)
Comprehensive income attributable to SEI Investments	$ 308,331	$ 283,372	$ 211,187

Consolidated Statements Of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Unrealized holding gains (losses) during the period, income tax (benefit) expense	$ (592)	$ (954)	$ 86
Reclassification adjustment for gains realized in net income, income tax expense	$ 319	$ 170	$ 50

Consolidated Statements Of Changes In Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Capital In Excess Of Par Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	SEI Investments [Member]	Noncontrolling Interest [Member]
Beginning balance at Dec. 31, 2011		$ 1,765	$ 577,949	$ 443,702	$ 1,900
Beginning balance, shares at Dec. 31, 2011		176,506,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase and retirement of common stock		(75)	(19,370)	(135,819)
Purchase and retirement of common stock, shares		(7,528,000)
Issuance of common stock under the employee stock purchase plan		1	1,794
Issuance of common stock under the employee stock purchase plan, shares		105,000
Issuance of common stock upon exercise of stock options		31	47,613
Issuance of common stock upon exercise of stock options, shares	3,136,000	3,137,000
Stock-based compensation	(15,736)		15,736
Tax benefit on stock options exercised			583
Net income attributable to SEI Investments Company	206,848			206,848
Dividends declared ($0.46, $0.42 and $0.63 per share)	(108,817)			(108,817)
Other comprehensive (loss) income	6,159				4,339
Total SEI Investments Shareholders' Equity						1,038,180
Noncontrolling Interest							19,149
Total Equity at Dec. 31, 2012	1,057,329	1,722	624,305	405,914	6,239
Ending balance, shares at Dec. 31, 2012		172,220,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase and retirement of common stock		(68)	(19,105)	(190,769)
Purchase and retirement of common stock, shares		(6,789,000)
Issuance of common stock under the employee stock purchase plan		1	1,950
Issuance of common stock under the employee stock purchase plan, shares		78,000
Issuance of common stock upon exercise of stock options		37	64,379
Issuance of common stock upon exercise of stock options, shares	3,733,000	3,733,000
Stock-based compensation	(37,865)		37,865
Tax benefit on stock options exercised			11,825
Net income attributable to SEI Investments Company	288,124			288,124
Dividends declared ($0.46, $0.42 and $0.63 per share)	(71,665)			(71,665)
Other comprehensive (loss) income	(5,203)				(4,752)
Total SEI Investments Shareholders' Equity						1,156,002
Noncontrolling Interest							0
Total Equity at Dec. 31, 2013	1,156,002	1,692	721,219	431,604	1,487
Ending balance, shares at Dec. 31, 2013	169,242,000	169,242,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase and retirement of common stock		(79)	(25,345)	(252,933)
Purchase and retirement of common stock, shares		(7,888,000)
Issuance of common stock under the employee stock purchase plan		1	2,197
Issuance of common stock under the employee stock purchase plan, shares		73,000
Issuance of common stock upon exercise of stock options		53	102,646
Issuance of common stock upon exercise of stock options, shares	5,261,000	5,261,000
Stock-based compensation	(13,463)		13,463
Tax benefit on stock options exercised			20,435
Net income attributable to SEI Investments Company	318,713			318,713
Dividends declared ($0.46, $0.42 and $0.63 per share)	(77,158)			(77,158)
Other comprehensive (loss) income	(10,382)				(10,382)
Total SEI Investments Shareholders' Equity						1,247,613
Noncontrolling Interest							0
Total Equity at Dec. 31, 2014	$ 1,247,613	$ 1,667	$ 834,615	$ 420,226	$ (8,895)
Ending balance, shares at Dec. 31, 2014	166,688,000	166,688,000

Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 318,713	$ 288,474	$ 208,034
Depreciation	22,448	22,497	22,586
Amortization	38,679	34,602	33,258
Equity in earnings of unconsolidated affiliates	(127,786)	(118,076)	(98,671)
Distributions received from unconsolidated affiliate	137,866	137,104	92,227
Stock-based compensation	13,463	37,865	15,736
Provision for losses on receivables	133	(154)	(119)
Deferred income tax expense	(3,330)	(22,825)	(1,191)
Gain from sale of SEI AK	(5,582)	(22,112)	0
Net realized gains from investments	(614)	(659)	(14,067)
Change in other long-term liabilities	1,720	1,575	(1,244)
Change in other assets	(5,886)	600	(619)
Other	(2,439)	(3,972)	6,680
Decrease (increase) in Restricted cash for broker-dealer operations	0	500	0
Decrease (increase) in Receivables from regulated investment companies	(9,029)	(8,280)	(5,284)
Decrease (increase) in Receivables	(7,888)	(17,513)	(30,852)
Decrease (increase) in Other current assets	(2,027)	1,971	(282)
Increase (decrease) in Accounts payable	(6,283)	5,000	9,249
Increase (decrease) in Accrued liabilities	12,873	15,102	21,627
Increase (decrease) in Deferred revenue	(228)	(475)	422
Total adjustments	56,090	62,750	49,456
Net cash provided by operating activities	374,803	351,224	257,490
Cash flows from investing activities:
Additions to restricted cash	(301)	0	0
Additions to property and equipment	(28,469)	(16,351)	(23,070)
Additions to capitalized software	(34,877)	(39,500)	(31,004)
Purchases of marketable securities	(56,754)	(57,560)	(33,662)
Prepayments and maturities of marketable securities	38,973	40,257	53,352
Sales of marketable securities	24,461	7,317	54,830
Purchases of other investments	(2,000)	(2,604)	(3,819)
Sale of subsidiary, net of cash transferred	5,582	6,028	0
Net cash (used in) provided by investing activities	(53,385)	(62,413)	16,627
Cash flows from financing activities:
Purchase and retirement of common stock	(275,788)	(206,577)	(157,543)
Proceeds from issuance of common stock	104,897	66,367	49,439
Tax benefit on stock options exercised	20,435	11,825	583
Payment of dividends	(74,294)	(34,400)	(135,335)
Net cash used in financing activities	(224,750)	(162,785)	(242,856)
Effect of exchange rate changes on cash and cash equivalents	(7,495)	0	0
Net increase in cash and cash equivalents	89,173	126,026	31,261
Cash and cash equivalents, beginning of year	578,273	452,247	420,986
Cash and cash equivalents, end of year	667,446	578,273	452,247
Interest paid	458	458	367
Income taxes paid	151,250	163,834	113,160
Non-cash financing activities
Dividends declared but not paid	$ 40,178	$ 37,314	$ 0

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Nature of Operations

SEI Investments Company (the Company), a Pennsylvania corporation, provides investment processing, investment management, and investment operations solutions to financial institutions, financial advisors, institutional investors, investment managers and ultra-high-net-worth families in the United States, Canada, the United Kingdom, continental Europe and other various locations throughout the world. Investment processing solutions consist of application and business process outsourcing services, professional services and transaction-based services. Revenues from investment processing solutions are recognized in Information processing and software servicing fees on the accompanying Consolidated Statements of Operations, except for fees earned associated with trade execution services.

Investment management programs consist of mutual funds, alternative investments and separate accounts. These include a series of money market, equity, fixed-income and alternative investment portfolios, primarily in the form of registered investment companies. The Company serves as the administrator and investment advisor for many of these products. Revenues from investment management programs are recognized in Asset management, administration and distribution fees on the accompanying Consolidated Statements of Operations.

Investment operations solutions offer investment managers support for traditional investment products such as mutual funds, collective investment trusts, exchange-traded funds, and institutional and separate accounts, by providing outsourcing services including fund and investment accounting, administration, reconciliation, investor servicing and client reporting. These solutions also provide support to managers focused on alternative investments who manage hedge funds, funds of hedge funds, private equity funds and real estate funds, across registered, partnership and separate account structures domiciled in the United States and overseas. Revenues from investment operations solutions are recognized in Asset management, administration and distribution fees on the accompanying Consolidated Statements of Operations.

Principles of Consolidation

The Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries and entities in which it holds a controlling financial interest. The Company determines whether it has a controlling financial interest either by its decision-making ability through voting interests or by the extent of the Company’s participation in the economic risks and rewards of the entity through variable interests. The Company’s principal subsidiaries are SEI Investments Distribution Co. (SIDCO), SEI Investments Management Corporation (SIMC), SEI Private Trust Company (SPTC), SEI Trust Company (STC), SEI Global Services, Inc. (SGSI) and SEI Investments (Europe) Limited (SIEL). All intercompany accounts and transactions have been eliminated.

The Company accounts for investments in unconsolidated entities that are 20 percent to 50 percent owned or are 20 percent or less owned and have the ability to exercise significant influence over the operating and financial policies of the entity under the equity method of accounting. Under this method of accounting, the Company’s interest in the net assets of unconsolidated entities is reflected in Investment in unconsolidated affiliates on the accompanying Consolidated Balance Sheet and its interest in the earnings or losses of unconsolidated entities is reflected in Equity in earnings of unconsolidated affiliates on the accompanying Consolidated Statement of Operations.

Variable Interest Entities

The Company has involvement with various variable interest entities (VIE or VIEs). These VIEs consist of LSV Employee Group III, LLC (LSV Employee Group III) and investment products established for clients created in the form of various types of legal entity structures. According to the most recent accounting guidance issued by the Financial Accounting Standards Board (FASB), the determination of whether a company is required to consolidate an entity is based on, among other things, an entity’s purpose and design, a company’s ability to direct the activities of the entity that most significantly impact the entity’s economic performance, and whether a company is obligated to absorb losses or receive benefits that could be potentially significant to the entity. The guidance requires ongoing reassessments of whether an enterprise is the primary beneficiary of a VIE and requires disclosures about an enterprises involvement in VIEs.

The FASB deferred the accounting guidance for certain types of investment entities. The deferral allows asset managers that have no obligation to fund potentially significant losses of an investment entity to continue to apply the previous guidance to investment entities that have attributes of entities defined in the “Investment Company Guide.” The deferral applies to many mutual funds, hedge funds, private equity funds, venture capital and certain other types of entities. Also, money market funds subject to rule 2a-7 of the Investment Company Act of 1940 qualify for deferral. However, the deferral does not apply to the new disclosure requirements. All of the Company’s investment products where the Company is the sponsor and/or investment manager that are VIEs qualify for the deferral; therefore, the Company will continue to apply the previous guidance for the consolidation of VIEs (See Note 3).

Management’s Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Revenue Recognition

The Company’s principal sources of revenues are: (1) asset management, administration and distribution fees earned based upon a contractual percentage of net assets under management or administration; (2) information processing and software servicing fees that are either recurring and primarily earned based upon the number of trust accounts being serviced or non-recurring and based upon project-oriented contractual agreements related to client implementations; and (3) transaction-based fees for providing trade-execution services. The Company’s revenues are based on contractual arrangements. Revenues are recognized in the periods in which the related services are performed provided that persuasive evidence of an agreement exists, the fee is fixed or determinable, and collectibility is reasonably assured. Cash received by the Company in advance of the performance of services is deferred and recognized as revenue when earned. Reimbursements received for out-of-pocket expenses incurred are recorded as revenue. Certain portions of the Company’s revenues require management’s consideration of the nature of the client relationship in determining whether to recognize as revenue the gross amount billed or net amount retained after payments are made to suppliers for certain services related to the product or service offering.

Cash and Cash Equivalents

The Company considers investment instruments purchased with an original maturity of three months or less to be cash equivalents. Cash and cash equivalents include $435,268 and $387,201 at December 31, 2014 and 2013, respectively, primarily invested in SEI-sponsored open-ended money market mutual funds. The SEI-sponsored mutual funds are considered Level 1 assets.

Restricted Cash

Restricted cash includes $5,000 at December 31, 2014 and 2013 segregated for regulatory purposes related to trade-execution services conducted by SIEL. Restricted cash also includes $500 at December 31, 2014 and 2013 segregated in special reserve accounts for the benefit of SIDCO customers in accordance with certain rules established by the Securities and Exchange Commission for broker-dealers.

Allowances for Doubtful Accounts

The Company provides an allowance for doubtful accounts equal to the estimated uncollectible amounts. The Company’s estimate is based on historical collection experience and a review of the current status of trade accounts receivable.

Concentration of Credit Risk

Financial instruments which potentially expose the Company to concentrations of credit risk consist primarily of cash equivalents and trade receivables. Cash equivalents are principally invested in short-term money market funds or placed with major banks and high-credit qualified financial institutions. Cash deposits maintained with institutions are in excess of federally insured limits. Concentrations of credit risk with respect to our receivables are limited due to the large number of clients and their dispersion across geographic areas. No single group or customer represents greater than ten percent of total accounts receivable.

Property and Equipment

Property and Equipment are recorded at cost. Expenditures for major additions and improvements are capitalized and minor replacements, maintenance, and repairs are charged to expense as incurred. Construction in progress includes the cost of construction and other direct costs attributable to the construction. When property and equipment are retired or disposed of, the related cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the results of operations for the respective period. Depreciation is provided over the estimated useful lives using the straight line method for financial statement purposes. No provision for depreciation is made for construction in progress until such time as the relevant assets are completed and put into service. The Company uses other depreciation methods, generally accelerated, for tax purposes where appropriate. Buildings and building improvements are depreciated over 25 to 39 years. Equipment, purchased software and furniture and fixtures have useful lives ranging from 3 to 5 years. Amortization of leasehold improvements is computed using the straight line method over the shorter of the remaining lease term or the estimated useful lives of the improvements.

Marketable Securities

The classification of investments in marketable securities is determined at the time of purchase and reevaluated at each balance sheet date. Debt and equity securities classified as available-for-sale are reported at fair value as determined by the most recently traded price of each security at the balance sheet date. Unrealized gains and losses, net of income taxes, are reported as a separate component of comprehensive income. SIDCO, the Company’s broker-dealer subsidiary, reports changes in fair value of marketable securities through current period earnings due to specialized accounting practices related to investments by broker-dealers. The Company records its investments in funds sponsored by LSV on the accompanying Consolidated Balance Sheets at fair value. Unrealized gains and losses from the change in fair value of these securities are recognized in current period earnings. The specific identification method is used to compute the realized gains and losses on all of the Company’s marketable securities (See Note 6).

The Company evaluates the realizable value of its marketable securities on a quarterly basis. In the event that the carrying value of an investment exceeds its fair value and the decline in value is determined to be other-than-temporary, an impairment charge is recorded and a new cost basis for the investment is established. Some of the factors considered in determining other-than-temporary impairment for equity securities include, but are not limited to, significant or prolonged declines in the fair value of the investments, the Company’s ability and intent to retain the investment for a period sufficient to allow the value to recover, and the financial condition of the investment. Some of the factors considered in determining other-than-temporary impairment for debt securities include, but are not limited to, the intent of management to sell the security, the likelihood that the Company will be required to sell the security before recovering its cost, and management’s expectation to recover the entire amortized cost basis of the security even if there is no intent to sell the security.

Fair Value of Financial Instruments

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The fair value hierarchy describes three levels of inputs that may be used by the Company to measure fair value:

Level 1 – Quoted prices in active markets for identical assets or liabilities without adjustment. The Company’s Level 1 assets primarily include investments in mutual funds sponsored by SEI that are quoted daily.

Level 2 – Observable inputs other than Level 1 prices, such as quoted prices for similar assets, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 financial assets consist of Government National Mortgage Association (GNMA) mortgage-backed securities, Federal Home Loan Bank (FHLB) and other U.S. government agency short-term notes and investment grade commercial paper, and investment funds sponsored by LSV. The investments in GNMA mortgage-backed securities were purchased for the sole purpose of satisfying applicable regulatory requirements imposed on our wholly-owned limited purpose federal thrift subsidiary, SPTC. The investments in FHLB and other U.S. government agency short-term notes and investment grade commercial paper were purchased as part of a cash management program requiring only short term, top-tier investment grade government and corporate securities. The investment funds sponsored by LSV primarily invest in equity securities of non-U.S. developed nations which are traded in active markets.

Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment by management. The Company had no Level 3 financial assets at December 31, 2014 or 2013.

The fair value of an asset or liability may include inputs from more than one level in the fair value hierarchy. The lowest level of significant inputs used to value the asset or liability determines which level the asset or liability is classified in its entirety. Transfers between levels of the fair value hierarchy are reported at fair value as of the beginning of the period in which the transfers occur.

See Note 5 for information on related disclosures regarding fair value measurements.

Capitalized Software

Costs incurred for the development of internal use software to be offered in a hosting arrangement is capitalized during the development stage of the software application. These costs include direct external and internal costs to design the software configuration and interfaces, coding, installation, and testing. Costs incurred during the preliminary and post-implementation stages of the software application are expensed as incurred. Costs associated with significant enhancements to a software application are capitalized while costs incurred to maintain existing software applications are expensed as incurred. The capitalization of software development costs requires considerable judgment by management with respect to certain external factors, including, but not limited to, technological and economic feasibility, and estimated economic life. Amortization of capitalized software development costs begins when the product is ready for its intended use. Capitalized software development costs are amortized on a product-by-product basis using the straight-line method over the estimated economic life of the product or enhancement.

The Company's capitalized software development costs primarily relate to the further development of the SEI Wealth Platform^SM(the Platform). The initial version of the Platform was placed into service in July 2007. Further enhancements and upgrades will continue to occur. As of December 31, 2014, the net book value of the Platform was $309,040. The Company capitalized $34,877, $39,500 and $31,004 of software development costs during 2014, 2013 and 2012, respectively. Included in the amount for 2013 is a one-time contractual payment of $8,812 to exercise a conversion option in lieu of periodic fee payments pertaining to a software license for functionality utilized by the Platform.

The Platform has an estimated useful life of 15 years and a weighted average remaining life of 7.5 years. Amortization expense for the Platform was $38,357, $34,045 and $32,177 in 2014, 2013 and 2012, respectively, and is included in Amortization expense on the accompanying Consolidated Statements of Operations. During 2012, the Company decided to discontinue the use of specific functionality within the Platform and expensed the remaining net book value of $2,661 related to previously capitalized software development costs of the component. This cost is included in total amortization expense on the accompanying Consolidated Statements of Operations.

The Company evaluates the carrying value of capitalized software development costs when circumstances indicate the carrying value may not be recoverable. The review of capitalized software development costs for impairment requires significant assumptions about operating strategies, underlying technologies utilized, and external market factors. External market factors include, but are not limited to, expected levels of competition, barriers to entry by potential competitors, stability in the target market and governmental regulations. The Company did not recognize any impairment charges related to its capitalized software development costs in 2014 or 2013.

Income Taxes

The Company applies the asset and liability approach to account for income taxes whereby deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The components of the deferred tax assets and liabilities are individually classified as current and non-current based on their characteristics.

Foreign Currency Translation

The assets and liabilities and results of operations of the Company’s foreign subsidiaries are measured using the foreign subsidiary’s local currency as the functional currency. Assets and liabilities have been translated into U.S. dollars using the rates of exchange at the balance sheet dates. The results of operations have been translated into U.S. dollars at average exchange rates prevailing during the period. The resulting translation gain and loss adjustments are recorded as a separate component of comprehensive income.

Transaction gains and losses from exchange rate fluctuations are included in the results of operations in the periods in which they occur. There were no material gains or losses from exchange rate fluctuations in 2014, 2013 or 2012.

Earnings Per Common Share

Basic earnings per common share is computed by dividing net income attributable to SEI Investments common shareholders by the weighted average number of common shares outstanding during the period. Diluted earnings per common share is computed by dividing net income attributable to SEI Investments common shareholders by the combination of the weighted average number of common shares outstanding and the dilutive potential common shares, such as stock options, outstanding during the period.

The calculations of basic and diluted earnings per share for 2014, 2013 and 2012 are:



	For the Year Ended December 31, 2014
	Net income attributable to SEI (Numerator)		Shares (Denominator)	Per-Share Amount
Basic earnings per common share	$	318,713	168,246,000	$	1.89
Dilutive effect of stock options	—		4,319,000
Diluted earnings per common share	$	318,713	172,565,000	$	1.85



	For the Year Ended December 31, 2013
	Net income attributable to SEI (Numerator)		Shares (Denominator)	Per-Share Amount
Basic earnings per common share	$	288,124	171,561,000	$	1.68
Dilutive effect of stock options	—		4,157,000
Diluted earnings per common share	$	288,124	175,718,000	$	1.64



	For the Year Ended December 31, 2012
	Net income attributable to SEI (Numerator)		Shares (Denominator)	Per-Share Amount
Basic earnings per common share	$	206,848	174,295,000	$	1.19
Dilutive effect of stock options	—		1,577,000
Diluted earnings per common share	$	206,848	175,872,000	$	1.18

Employee stock options to purchase approximately 10,166,000, 7,736,000 and 13,202,000 shares of common stock, with an average exercise price per share of $30.00, $30.54 and $24.76, were outstanding during 2014, 2013 and 2012, respectively, but not included in the computation of diluted earnings per common share because the option’s exercise price was greater than the average market price of the Company’s common stock or the performance conditions have not been satisfied or would have been satisfied if the reporting date was the end of the contingency period and the effect on diluted earnings per common share would have been anti-dilutive (See Note 8).

Stock-Based Compensation

Stock-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense over the requisite service period, which is the vesting period. The Company uses historical data to estimate pre-vesting forfeitures and record stock-based compensation expense only for those awards that are expected to vest. The amount of stock-based compensation expense that is recognized in a given period is dependent upon management’s estimate of when the vesting targets are expected to be achieved. If this estimate proves to be inaccurate, the remaining amount of stock-based compensation expense could be accelerated, spread out over a longer period, or reversed (See Note 8).

New Accounting Pronouncements

On May 28, 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (ASU 2014-09), requiring an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. The updated standard permits the use of either the retrospective or cumulative effect transition method. Early adoption is not permitted. ASU 2014-09 becomes effective for the Company during the first quarter 2017. The Company is currently evaluating the transition method that will be elected and the effect that the updated standard will have on its consolidated financial statements and related disclosures.

On February 18, 2015, the FASB issued Accounting Standards Update No. 2015-02, Consolidation (Topic 810) - Amendments to the Consolidation Analysis (ASU 2015-02). The new guidance applies to entities in all industries and provides a new scope exception to registered money market funds and similar unregistered money market funds. It makes targeted amendments to the current consolidation guidance and ends the deferral granted to investment companies from applying the VIE guidance. ASU 2015-02 becomes effective for the Company during the first quarter 2016. The Company is currently evaluating the effect that the standard will have on its consolidated financial statements and related disclosures.

Reclassifications

Certain prior year amounts have been reclassified to conform to current year presentation.

- Definition

The entire disclosure for all significant accounting policies of the reporting entity.

+ References+ Details

Investment In Unconsolidated Affiliates

12 Months Ended

Dec. 31, 2014

Equity Method Investments and Joint Ventures [Abstract]

Investment In Unconsolidated Affiliates

Investment in Unconsolidated Affiliates

LSV Asset Management

The Company has an investment in the general partnership LSV Asset Management (LSV), a registered investment advisor that provides investment advisory services primarily to institutions, including pension plans and investment companies. LSV is currently an investment sub-advisor for a limited number of SEI-sponsored mutual funds. As of December 31, 2014, the Company's total partnership interest in LSV was approximately 39.3 percent. The Company accounts for its interest in LSV using the equity method because of its less than 50 percent ownership. The Company’s interest in the net assets of LSV is reflected in Investment in unconsolidated affiliates on the accompanying Consolidated Balance Sheets and its interest in the earnings of LSV is reflected in Equity in earnings of unconsolidated affiliates on the accompanying Consolidated Statements of Operations.

At December 31, 2014, the Company’s total investment in LSV was $52,940. The Company’s proportionate share in the earnings of LSV was $140,211, $118,983 and $99,989 in 2014, 2013 and 2012, respectively. The Company receives partnership distributions from LSV on a quarterly basis. The Company received partnership distribution payments from LSV of $137,866, $137,104 and $92,227 in 2014, 2013 and 2012, respectively. The Company received an additional partnership distribution payment from LSV during 2013 due to a change in the payment schedule.

These tables contain condensed financial information of LSV:



Condensed Statement of Operations Year ended December 31,	2014		2013		2012
Revenues	$	422,064	$	354,094	$	296,261
Net income	$	356,824	$	302,316	$	250,165



Condensed Balance Sheets December 31,	2014		2013
Current assets	$	133,657	$	118,630
Non-current assets	2,269		2,588
Total assets	$	135,926	$	121,218

Current liabilities	$	35,208	$	26,103
Partners’ capital	100,718		95,115
Total liabilities and partners’ capital	$	135,926	$	121,218

Guaranty Agreement with LSV Employee Group II

In April 2011, a group of existing employees of LSV formed a new limited liability company, LSV Employee Group II, and agreed to purchase a partnership interest of an existing LSV employee for $4,300 of which $3,655 was financed through a term loan with Bank of America, N.A. The Company provided an unsecured guaranty to the lenders of all the obligations of LSV Employee Group II. In May 2014, LSV Employee Group II made the final principal payment for the term loan and the Company has no further obligation related to the guaranty provided for LSV Employee Group II.

Guaranty Agreement with LSV Employee Group III

In October 2012, a group of existing employees of LSV formed a new limited liability company called LSV Employee Group III and agreed to purchase a portion of the partnership interest of existing LSV employees for $77,700, of which $69,930 was financed through syndicated term loan facilities contained in a credit agreement with The PrivateBank and Trust Company. LSV Employee Group III owns the purchased partnership interest. The Company provided an unsecured guaranty for $45,000 of the obligations of LSV Employee Group III to the lenders through a guaranty agreement. In addition, LSV agreed to provide an unsecured guaranty for the remaining $24,930 of the obligations of LSV Employee Group III to the lenders through a separate guaranty agreement. In September 2014, LSV Employee Group III made the final principal payment related to the term loan guaranteed by LSV.

With regard to the loan facility guaranteed by the Company, the lenders will have the right to seek payment from the Company in the event of a default by LSV Employee Group III. The loan facility has a five year term and will be repaid from the quarterly distributions of LSV. No principal payments were made by LSV Employee Group III on the loan facility guaranteed by the Company until the separate loan facility guaranteed by LSV was fully repaid.

The Company’s direct interest in LSV was unchanged as a result of this transaction. The Company has determined that LSV Employee Group III is a VIE; however, the Company is not considered the primary beneficiary because it does not have the power to direct the activities that most significantly impact the economic performance of LSV Employee Group III either directly or through any financial responsibility from the guaranty.

As of January 30, 2015, the remaining unpaid principal balances of the term loan guaranteed by the Company was $38,658. The Company, in its capacity as guarantor, currently has no obligation of payment relating to the term loan of LSV Employee Group III and, furthermore, fully expects that LSV Employee Group III will meet all of their future obligations regarding the term loan.

Investment in Gao Fu Limited

The Company has an investment in Gao Fu, a wealth services firm based in Shanghai, China. The Company accounts for its interest in Gao Fu using the equity method. As of December 31, 2014, the Company owns approximately 27.6 percent of the outstanding voting stock of Gao Fu. The Company's interest in the net assets of Gao Fu is reflected in Investment in unconsolidated affiliates on the accompanying Consolidated Balance Sheets and its interest in the gains and losses of Gao Fu is reflected in Equity in earnings of unconsolidated affiliates on the accompanying Consolidated Statements of Operations.

The Company's proportionate share in the losses of Gao Fu was $1,159, $907 and $1,318 in 2014, 2013 and 2012, respectively. The Company's investment in Gao Fu resulted from a series of cash purchases of common stock between 2011 and 2013 which, in total, amounted to $13,000. In June and December of 2014, the Company funded an aggregate of $3,000 of convertible loans to Gao Fu. The June 2014 convertible loan agreement contains specific revenue and net income targets for Gao Fu to achieve by December 31, 2014. In December 2014, the Company conducted a review of the financial statements of Gao Fu and determined that the achievement of such performance targets as stipulated in the June 2014 convertible loan agreement was unlikely. As a result, the Company wrote down its investment in Gao Fu to its net realizable value based on its ownership percentage of the remaining net assets of the firm and recognized an impairment charge of $11,266 during the three months ended December 31, 2014. The impairment charge is reflected in Equity in earnings of unconsolidated affiliates on the accompanying Consolidated Statements of Operations.

- Definition

The entire disclosure for equity method investments and joint ventures. Equity method investments are investments that give the investor the ability to exercise significant influence over the operating and financial policies of an investee. Joint ventures are entities owned and operated by a small group of businesses as a separate and specific business or project for the mutual benefit of the members of the group.

+ References+ Details

Variable Interest Entities - Investment Products	12 Months Ended
Variable Interest Entities - Investment Products	Dec. 31, 2014
Variable Interest Entities Disclosure [Abstract]
Variable Interest Entities - Investment Products	Variable Interest Entities – Investment Products The Company has created numerous investment products for its clients in various types of legal entity structures. The Company serves as the Manager, Administrator and Distributor for these investment products and may also serve as the Trustee for some of the investment products. Clients are the equity investors and participate in proportion to their ownership percentage in the net income or loss and net capital gains or losses of the products, and, on liquidation, will participate in proportion to their ownership percentage in the remaining net assets of the products after satisfaction of outstanding liabilities. An entity that lacks decision-making rights is a VIE. In some circumstances, the Manager or Trustee of the Company’s investment products controls the governing decisions about the investment activities with respect to the ongoing operations of the investment products without the equity investors possessing the right to remove the Manager or Trustee. Therefore, the equity investors, as a group, do not have the ability to make decisions that have an impact on the ongoing activities of such investment products. Consequently, some of the Company’s investment products have been determined to be VIEs at inception. The VIEs are marketed with investment objectives to generate positive returns; however, the nature of such investments exposes the investors to the risk that the value of the VIEs may increase or decrease. The purpose and design of the VIEs are to achieve the investment objective by implementing strategies which are designed to minimize potential losses; however, there is no assurance given that these strategies will be successful. The Company does not have a significant equity investment in any of the VIEs and does not have an obligation to enter into any guarantee agreements with the VIEs. The fees paid to the decision maker of a VIE are considered to be variable interests if the decision maker is not subject to substantive kick-out rights. The fees paid to the Company represent a variable interest when the decision maker is not subject to substantive kick-out rights. The Company is not the primary beneficiary of the VIEs because the expected fees and the expected return on any investment into the VIE by the Company relative to the expected returns of the VIE to the equity investor holders does not approach 50 percent of the expected losses or gains of the VIEs. Therefore, the Company is not required to consolidate any investment products that are VIEs into its financial statements. The Company’s variable interest in the VIEs, which consists of management fees and in some situations, seed capital, would not be considered a significant variable interest. The risks to the Company associated with its involvement with any of the investment products that are VIEs are limited to the cash flows received from the revenue generated for asset management, administration and distribution services and any equity investments in the VIEs. Both of these items are immaterial. The Company has no other financial obligation to the VIEs. Amounts relating to fees due from the VIEs included in Receivables and amounts relating to equity investments in the VIEs included in Investments Available for Sale on the Company’s Consolidated Balance Sheets are immaterial to the total current assets of the Company.

Composition of Certain Financial Statement Captions

12 Months Ended

Dec. 31, 2014

Items Included in Consolidated Statement of Financial Condition [Abstract]

Composition of Certain Financial Statement Captions

Receivables

Receivables on the accompanying Consolidated Balance Sheets consist of:



	2014			2013
Trade receivables	$	48,394		$	44,502
Fees earned, not billed	139,038			128,248
Other receivables	7,771			14,565
	195,203			187,315
Less: Allowance for doubtful accounts	(784		)	(651		)
Receivables, net	$	194,419		$	186,664

Fees earned, not billed represents receivables earned but unbilled and results from timing differences between services provided and contractual billing schedules. These billing schedules generally provide for fees to be billed on a quarterly basis.

Property and Equipment

Property and Equipment on the accompanying Consolidated Balance Sheets consists of:



	2014			2013
Buildings	$	149,890		$	138,426
Equipment	78,266			70,117
Land	9,997			9,929
Purchased software	104,964			96,268
Furniture and fixtures	16,944			17,060
Leasehold improvements	5,675			4,670
Construction in progress	1,094			2,589
	366,830			339,059
Less: Accumulated depreciation	(241,295		)	(220,064		)
Property and Equipment, net	$	125,535		$	118,995

Depreciation expense related to property and equipment for 2014, 2013 and 2012 was $22,448, $22,497 and $22,586, respectively.

Other Assets

Other assets consist of long-term prepaid expenses, deposits, other investments at cost and various other assets. Amortization expense for certain other assets for 2014 and 2013 was $227 and for 2012 was $611.

Accrued Liabilities

Accrued Liabilities on the accompanying Consolidated Balance Sheets consist of:



	2014		2013
Accrued employee compensation	$	73,269	$	69,256
Accrued employee benefits and other personnel	6,482		9,647
Accrued consulting, outsourcing and professional fees	18,915		19,311
Accrued sub-advisory, distribution and other asset management fees	31,913		25,018
Accrued dividend payable	40,178		37,314
Other accrued liabilities	36,672		27,577
Accrued liabilities	$	207,429	$	188,123

Fair Value Measurements

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Fair Value Measurements

The fair value of the Company’s financial assets and liabilities is determined in accordance with the fair value hierarchy. The fair value of the Company’s Level 1 financial assets consist mainly of investments in open-ended mutual funds that are quoted daily. The fair value of the Company’s Level 2 financial assets consist of GNMA mortgage-backed securities held by SPTC, FHLB and other U.S. government agency short-term notes and investment grade commercial paper held by SIDCO, and investment funds sponsored by LSV. The financial assets held by SIDCO were purchased as part of a cash management program requiring only short term, top-tier investment grade government and corporate securities. The financial assets held by SPTC are debt securities issued by GNMA and are backed by the full faith and credit of the U.S. government. These securities were purchased for the sole purpose of satisfying applicable regulatory requirements as a limited-purpose federal thrift subsidiary and have maturity dates which range from 2020 to 2043.

The valuation of the Company's Level 2 financial assets held by SIDCO and SPTC are based upon securities pricing policies and procedures utilized by third-party pricing vendors. As a practical expedient, the Company relies on the net asset values (NAVs) of the investment funds sponsored by LSV as the fair value. The NAVs of the funds are calculated by the funds' independent custodian and are derived from the fair values of the underlying investments as of the reporting date. The Company had no Level 3 financial assets or liabilities at December 31, 2014 or 2013.

Valuation of GNMA, Other U.S. Government Agency Securities and Investment Grade Commercial Paper

All of the Company's investments in GNMA, FHLB and other U.S. government agency securities and investment grade commercial paper are held in accounts at well-established financial institutions. The Company's selection of a financial institution for the purpose of purchasing securities considered a number of various factors including, but not limited to, securities pricing policies and procedures utilized by that financial institution. Each financial institution utilizes the services of independent pricing vendors. These vendors utilize evaluated and industry accepted pricing models that vary by asset class and incorporate available trade, bid and other market information to determine the fair value of the securities. The market inputs, listed in approximate order of priority, include: benchmark yields, reported trade, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data. The Company evaluated the information regarding the pricing methodologies and processes utilized by the independent pricing vendors during the selection process of the financial institution. The Company analyzed this information for the purpose of classifying the securities into the appropriate level within the fair value hierarchy and to ensure that each pricing model for each asset class provided the fair value of those specific securities in accordance with generally accepted accounting principles. The Company continually monitors the price of each security for any unanticipated deviations from the previously quoted price or deviations from anticipated changes in a security's price based upon an assessment of market factors and other factors relative to a specific issue expected to affect a security's price. In the event a security price changed in excess of management's pre-established tolerance levels, additional analysis is conducted which may include the comparison of the security's price as determined by other independent pricing vendors. The Company's investments in GNMA, FHLB and other U.S. government agency securities and investment grade commercial paper have been recorded at the prices provided by the independent pricing vendor without adjustment.

The fair value of certain financial assets and liabilities of the Company was determined using the following inputs:



	December 31, 2014
	Fair Value Measurements at Reporting Date Using
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Assets
Equity available-for-sale securities	$	11,588	$	11,588	$	—
Fixed-income available-for-sale securities	66,021		—		66,021
Fixed income securities owned	21,175		—		21,175
Investment funds sponsored by LSV	4,523		—		4,523
	$	103,307	$	11,588	$	91,719



	December 31, 2013
	Fair Value Measurements at Reporting Date Using
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Assets
Equity available-for-sale securities	$	11,633	$	11,633	$	—
Fixed-income available-for-sale securities	71,690		—		71,690
Fixed income securities owned	21,133		—		21,133
Investment funds sponsored by LSV	4,849		4,849		—
	$	109,305	$	16,482	$	92,823

Marketable Securities

12 Months Ended

Dec. 31, 2014

Marketable Securities [Abstract]

Marketable Securities

Investments Available For Sale

Investments available for sale classified as non-current assets consist of:



	At December 31, 2014
	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Fair Value
SEI-sponsored mutual funds	$	8,685	$	134	$	(95	)	$	8,724
Equities and other mutual funds	2,695		169		—			2,864
Debt securities	64,333		1,688		—			66,021
	$	75,713	$	1,991	$	(95	)	$	77,609



	At December 31, 2013
	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value
SEI-sponsored mutual funds	$	7,612	$	1,242	$	—	$	8,854
Equities and other mutual funds	2,615		164		—		2,779
Debt securities	71,280		410		—		71,690
	$	81,507	$	1,816	$	—	$	83,323

Net unrealized holding gains at December 31, 2014 and 2013 were $1,193 (net of income tax expense of $703) and $1,386 (net of income tax expense of $430), respectively. These net unrealized gains are reported as a separate component of Accumulated other comprehensive (loss) income on the accompanying Consolidated Balance Sheets.

There were gross realized gains of $1,401 and gross realized losses of $448 from available-for-sale securities during 2014. In 2013, there were gross realized gains of $1,236 and gross realized losses of $772 from available-for-sale securities. There were no material gross realized gains or losses from available-for-sale securities during 2012. Gains and losses from available-for-sale securities, including amounts reclassified from accumulated comprehensive income, are reflected in Net gain from investments on the accompanying Consolidated Statements of Operations.

Investments in Affiliated Funds

The Company has an investment related to the startup of investment funds sponsored by LSV. The Company records this investment on the accompanying Consolidated Balance Sheets at fair value. Unrealized gains and losses from the change in fair value of these funds are recognized in Net gain from investments on the accompanying Consolidated Statements of Operations.

The investment primarily consists of U.S. dollar denominated funds that invests in equity securities of Canadian, Australian and Japanese companies. The underlying securities held by the funds are translated into U.S. dollars within the funds. The funds had a fair value of $4,523 and $4,849 at December 31, 2014 and 2013, respectively. The Company recognized losses of $326 and gains of $143 and $1,004 from the change in fair value of the funds during 2014, 2013 and 2012, respectively.

Securities Owned

The Company’s broker-dealer subsidiary, SIDCO, has investments in U.S. government agency and commercial paper securities with maturity dates less than one year. These investments are reflected as Securities owned on the accompanying Consolidated Balance Sheets. Due to specialized accounting practices applicable to investments by broker-dealers, the securities are reported at fair value and changes in fair value are recorded in current period earnings. The securities had a fair value of $21,175 and $21,133 at December 31, 2014 and 2013, respectively. There were no material net gains or losses from the change in fair value of the securities during 2014, 2013 and 2012.

- Definition

Tabular disclosure of marketable securities. This may consist of investments in certain debt and equity securities, short-term investments and other assets.

+ References+ Details

Line Of Credit	12 Months Ended
Line Of Credit	Dec. 31, 2014
Line of Credit Facility [Abstract]
Line Of Credit	Line of Credit On February 2, 2012, the Company entered into a five-year $300,000 Credit Agreement (the Credit Facility) with Wells Fargo Bank, National Association, and a syndicate of other lenders. The Credit Facility is scheduled to expire in February 2017, at which time any aggregate principal amount of loans outstanding becomes payable in full. Any borrowings made under the Credit Facility will accrue interest at 1.25 percent above the London Interbank Offer Rate (LIBOR). There is also a commitment fee equal to 0.15 percent per annum on the daily unused portion of the facility. The aggregate amount of the Credit Facility may be increased by an additional $100,000 under certain conditions set forth in the agreement. The Credit Facility contains covenants that restrict the ability of the Company to engage in mergers, consolidations, asset sales, investments, transactions with affiliates, or to incur liens, as defined in the agreement. In the event of a default under the Credit Facility, the Company would also be restricted from paying dividends on, or repurchasing, its common stock without the approval of the lenders. None of the covenants of the Credit Facility negatively affect the Company’s liquidity or capital resources. Both the interest rate and commitment fee prices may increase if the Company’s leverage ratio reaches certain levels. Upon the occurrence of certain financial or economic events, significant corporate events, or certain other events of default constituting an event of default under the Credit Facility, all loans outstanding may be declared immediately due and payable and all commitments under the Credit Facility may be terminated. The Company had no borrowings through the Credit Facility at December 31, 2014 or 2013. The Company was in compliance with all covenants of the Credit Facility during 2014. The Company incurred $458 during 2014 and 2013 and $585 during 2012 in commitment fees related to the Credit Facility which are reflected in Interest expense on the accompanying Consolidated Statements of Operations.

Shareholders' Equity

12 Months Ended

Dec. 31, 2014

Stockholders' Equity Note [Abstract]

Shareholders' Equity

Shareholders’ Equity

Stock-Based Compensation

On March 19, 2014, the Company’s Board of Directors approved the 2014 Omnibus Equity Compensation Plan (the 2014 Plan), which was later approved by the shareholders of the Company on May 21, 2014. The 2014 Plan became effective upon receipt of the shareholders' approval on May 21, 2014 and is the successor equity compensation plan to the 2007 Equity Compensation Plan (the 2007 Plan) which was merged with and into the 2014 Plan. The 2014 Plan provides for the grant of stock options, stock units, stock awards, stock appreciation rights, dividend equivalents and other stock-based awards.

Outstanding grants under the 2007 Plan will continue according to the terms in effect before the plan merger, but the outstanding shares will be issued or transferred under the 2014 Plan. Permitted grantees under the 2014 Plan include employees, non-employee directors and consultants who perform services for the Company. The plan is administered by the Compensation Committee of the Board of Directors of the Company. The Company has only non-qualified stock options outstanding under the 2014 Plan.

All outstanding stock options have performance-based vesting provisions that tie the vesting of stock options to the Company’s financial performance. The Company’s stock options vest at a rate of 50 percent when a specified diluted earnings per share target is achieved, and the remaining 50 percent when a second, higher-specified diluted earnings per share target is achieved. Options do not vest due to the passage of time but solely as a result of achievement of the financial vesting targets. Earnings per share targets are calculated exclusive of stock-based compensation expense, net of tax. The diluted earnings per share targets are established at time of grant and are measured annually on December 31. The amount of stock-based compensation expense is based upon management’s estimate of when the earnings per share targets may be achieved. If management’s estimate of the attainment of the earnings per share targets proves to be inaccurate, the remaining amount of stock-based compensation expense could be accelerated, spread out over a longer period, or reversed. This may cause volatility in the recognition of stock-based compensation expense in future periods and could materially affect the Company’s net income and net income per share.

The Company uses the Black-Scholes option pricing model to determine the fair value of stock options. The determination of the fair value of stock options on the date of grant using an option-pricing model is affected by the price of the Company’s common stock as well as other variables. These variables include expected stock price volatility over the term of the awards, actual and projected employee stock exercise behaviors, risk-free interest rate and expected dividends. The Company primarily uses historical data to estimate the variables used in the option-pricing model except expected volatility. The Company uses a combination of historical and implied volatility. The Company estimates forfeitures at the time of grant and may revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting forfeitures and record stock-based compensation expense only for those awards that are expected to vest. Stock-based compensation is amortized over the requisite service periods of the awards, which are generally the vesting periods.

The weighted average fair value of the Company’s stock options granted during 2014, 2013 and 2012 were $10.88, $10.45 and $6.73, respectively, using the following assumptions:



	2014		2013		2012
Expected term (in years)	6.79		6.92		6.75
Expected volatility	26.98	%	31.46	%	34.90	%
Expected dividend yield	1.15	%	1.21	%	1.46	%
Risk-free interest rate	2.04	%	2.12	%	1.03	%

The Company recognized stock-based compensation expense in its Consolidated Financial Statements in 2014, 2013 and 2012 as follows:



	2014			2013			2012
Stock-based compensation expense	$	13,463		$	37,865		$	15,736
Less: Deferred tax benefit	(4,704		)	(13,823		)	(5,650		)
Stock-based compensation expense, net of tax	$	8,759		$	24,042		$	10,086

During 2013, the Company revised its estimates of when some vesting targets were expected to be achieved. These changes in management’s estimates resulted in an increase of $19,637 in stock-based compensation expense in 2013.

As of December 31, 2014, there was approximately $45,115 of unrecognized compensation cost, adjusted for estimated forfeitures, related to unvested employee stock options that the Company expects will vest and be expensed through 2020 with a weighted average period of 2.4 years.

This table presents certain information relating to the Company’s stock option plans for 2014, 2013 and 2012:



	Number of Shares		Weighted Avg. Price
Balance as of December 31, 2011	27,043,000		$	20.06
Granted	2,470,000		22.40
Exercised	(3,136,000	)	15.19
Expired or canceled	(767,000	)	22.61
Balance as of December 31, 2012	25,610,000		$	20.81
Granted	2,281,000		33.67
Exercised	(3,733,000	)	17.26
Expired or canceled	(521,000	)	22.25
Balance as of December 31, 2013	23,637,000		$	22.58
Granted	2,293,000		40.05
Exercised	(5,261,000	)	19.52
Expired or canceled	(208,000	)	28.83
Balance as of December 31, 2014	20,461,000		$	25.26

Exercisable as of December 31, 2014	10,295,000		$	20.58
Available for future grant as of December 31, 2014	28,626,000

As of December 31, 2013 and 2012, there were 14,601,000 and 9,760,000 shares exercisable, respectively. The expiration dates for options outstanding at December 31, 2014 range from December 14, 2015 to December 9, 2024 with a weighted average remaining contractual life of 5.8 years.

Upon exercise of stock options, the Company will issue new shares of its common shares. The Company does not hold any shares in treasury. The total intrinsic value of options exercised during 2014 and 2013 was $83,196 and $47,392, respectively. The total options exercisable as of December 31, 2014 had an intrinsic value of $200,328. The total options outstanding as of December 31, 2014 had an intrinsic value of $302,441. The total intrinsic value for options outstanding and options exercisable is calculated as the difference between the market value of the Company’s common stock as of December 31, 2014 and the exercise price of the shares. The market value of the Company’s common stock as of December 31, 2014 was $40.04 as reported by the Nasdaq Stock Market, LLC.

This table summarizes information relating to all options outstanding and exercisable at December 31, 2014:



				Options Outstanding at December 31, 2014				Options Exercisable at December 31, 2014
Range of Exercise Prices (Per Share)				Number of Shares	Weighted Average Exercise Price (Per Share)		Weighted Average Remaining Contractual Life (Years)	Number of Shares	Weighted Average Exercise Price (Per Share)		Weighted Average Remaining Contractual Life (Years)
$	14.62	-	15.77	4,073,000	$	15.19	5.48	2,915,000	$	14.95	5.69
17.65		-	21.05	3,534,000	18.20		3.71	3,519,000	18.27		4.49
22.45		-	23.86	4,399,000	23.20		6.93	1,960,000	21.92		4.35
27.03		-	32.49	4,073,000	30.95		2.68	1,901,000	26.57		5.09
33.73		-	40.64	4,382,000	37.10		9.50	—	31.17		4.00
				20,461,000				10,295,000

Employee Stock Purchase Plan

The Company has an employee stock purchase plan that provides for offerings of common stock to eligible employees at a price equal to 85 percent of the fair market value of the stock at the end of the stock purchase period, as defined. The Company has reserved 15,600,000 shares for issuance under this plan. At December 31, 2014, 11,732,000 cumulative shares have been issued. There were no material costs incurred by the Company related to the employee stock purchase plan in 2014, 2013 and 2012.

Common Stock Buyback

The Board of Directors, under multiple authorizations, has authorized the purchase of the Company’s common stock on the open market or through private transactions. As of December 31, 2014, the Company had approximately $102,713 of authorization remaining for the purchase of common stock. The following table provides the total number of shares repurchased and the related total costs in 2014, 2013 and 2012:



Year	Total Number of Shares Repurchased	Total Cost
2014	7,888,000	$	278,357
2013	6,789,000	209,942
2012	7,528,000	155,264

The Company immediately retires its common stock when purchased. Upon retirement, the Company reduces Capital in excess of par value for the average capital per share outstanding and the remainder is charged against Retained earnings. If the Company reduces its Retained earnings to zero, any subsequent purchases of common stock will be charged entirely to Capital in excess of par value.

Rights Agreement

In December 2008, the Company’s Board of Directors declared a dividend distribution pursuant to a Rights Agreement (the Rights Agreement) which became effective on January 6, 2009. The purpose of the Rights Agreement is to deter coercive or unfair takeover tactics and to prevent a person or group (an Acquiring Person) from acquiring control of the Company without offering a fair price to all shareholders. Under the Rights Agreement, all common shareholders receive one Right for each common share outstanding. Each Right entitles the registered holder to purchase from the Company a unit consisting of one twenty-thousandths of a share of Series A Junior Participating Preferred Shares, $0.05 par value per share, or a combination of securities and assets of equivalent value, at a purchase price of $150.00 per unit, subject to adjustment. The Rights will become exercisable and trade separately from the common stock ten days days following a public announcement that an Acquiring Person has beneficial ownership of more than 20 percent of the outstanding common stock of the Company or the commencement of a tender or exchange offer that would result in an Acquiring Person owning 20 percent or more of the outstanding common stock of the Company. Upon exercise, holders, other than an Acquiring Person, will have the right to purchase the common stock of the Company equal to twice the value of the exercise price of the Rights. In lieu of requiring payment of the purchase price upon exercise of the Rights following certain events, the Company may permit the holders simply to surrender the Rights, in which event they will be entitled to receive common shares and other property, as the case may be, with a value of 50 percent of what could be purchased by payment of the full purchase price. The Rights, which do not have voting rights, will expire on January 6, 2019, and may be redeemed by the Company any time until ten days following the announcement of an Acquiring Person at a price of $0.01 per Right.

Cash Dividends

On May 21, 2014, the Board of Directors declared a cash dividend of $0.22 per share on the Company’s common stock, which was paid on June 24, 2014, to shareholders of record on June 16, 2014. On December 9, 2014, the Board of Directors declared a cash dividend of $0.24 per share on the Company’s common stock, which was paid on January 6, 2015, to shareholders of record on December 22, 2014.

The cash dividends declared in 2014, 2013 and 2012 were $77,158, $71,665 and $108,817 respectively. Cash dividends declared in 2012 includes a special cash dividend of $55,149 declared and paid in December 2012. The Board of Directors has indicated its intention to declare future cash dividends on a semiannual basis.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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+ Details

Accumulated Other Comprehensive Income (Loss)

12 Months Ended

Dec. 31, 2014

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Accumulated Other Comprehensive Income (Loss)

Other comprehensive income (loss) consists of net income and other gains and losses affecting shareholders’ equity that are excluded from net income. For the Company, other comprehensive income (loss) includes unrealized gains and losses on available for sale securities and foreign currency translation adjustments. The Company presents other comprehensive income (loss) in its Consolidated Statements of Comprehensive Income. Components of Accumulated other comprehensive income (loss) attributable to SEI Investments shareholders consisted of:



	Foreign Currency Translation Adjustments			Unrealized Holding Gains (Losses) on Investments			Accumulated Other Comprehensive Income (Loss)
Balance, January 1, 2012	$	(674	)	$	2,574		$	1,900

Other comprehensive income before reclassifications	4,084			341			4,425
Amounts reclassified from accumulated other comprehensive income	—			(86		)	(86		)
Net current-period other comprehensive income	4,084			255			4,339

Balance, December 31, 2012	$	3,410		$	2,829		$	6,239

Other comprehensive loss before reclassifications	(3,309		)	(1,149		)	(4,458		)
Amounts reclassified from accumulated other comprehensive income	—			(294		)	(294		)
Net current-period other comprehensive loss	(3,309		)	(1,443		)	(4,752		)

Balance, December 31, 2013	$	101		$	1,386		$	1,487

Other comprehensive loss before reclassifications	(10,189		)	441			(9,748		)
Amounts reclassified from accumulated other comprehensive income	—			(634		)	(634		)
Net current-period other comprehensive loss	(10,189		)	(193		)	(10,382		)

Balance, December 31, 2014	$	(10,088	)	$	1,193		$	(8,895	)

- Definition

The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.

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-Glossary Reclassification Adjustments

-URI http://asc.fasb.org/extlink&oid=6522872

+ Details

Employee Benefit Plan	12 Months Ended
Employee Benefit Plan	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plan	Employee Benefit Plan The Company has a tax-qualified defined contribution plan (the Plan). The Plan provides retirement benefits, including provisions for early retirement and disability benefits, as well as a tax-deferred savings feature. After satisfying certain requirements, participants are vested in employer contributions at the time the contributions are made. All Company contributions are discretionary and are made from available profits. The Company contributed $6,157, $5,664 and $5,168 to the Plan in 2014, 2013 and 2012, respectively.

- Definition

The entire disclosure for pension and other postretirement benefits.

+ References+ Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2014

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

The Company leases certain of its facilities, data processing equipment, and software under non-cancelable operating leases, some which contain escalation clauses for increased taxes and operating expenses. The Company has entered into maintenance agreements primarily for its data processing equipment. Rent expense was $23,011, $21,519 and $21,614 in 2014, 2013 and 2012, respectively.

The aggregate noncancellable minimum commitments at December 31, 2014 are:



2015	$	3,779
2016	3,023
2017	3,741
2018	6,704
2019 and thereafter	43,601
	$	60,848

In the ordinary course of business, the Company from time to time enters into contracts containing indemnification obligations of the Company. These obligations may require the Company to make payments to another party upon the occurrence of certain events including the failure by the Company to meet its performance obligations under the contract. These contractual indemnification provisions are often standard contractual terms of the nature customarily found in the type of contracts entered into by the Company. In many cases, there are no stated or notional amounts included in the indemnification provisions. There are no amounts reflected on the Consolidated Balance Sheets as of December 31, 2014 and 2013 related to these indemnifications.

In the normal course of business, the Company is party to various claims and legal proceedings.

SEI has been named in six lawsuits filed in Louisiana. Five lawsuits were filed in the 19th Judicial District Court for the Parish of East Baton Rouge. One of the five actions purports to set forth claims on behalf of a class and also names SPTC as a defendant. Two of the other actions also name SPTC as a defendant. All five actions name various defendants in addition to SEI, and, in all five actions, the plaintiffs purport to bring a cause of action against SEI and/or SPTC under the Louisiana Securities Act. Two of the five actions include claims for violations of the Louisiana Racketeering Act and possibly conspiracy. In addition, another group of plaintiffs filed a lawsuit in the 23rd Judicial District Court for the Parish of Ascension against SEI and SPTC and other defendants, asserting claims of negligence, breach of contract, breach of fiduciary duty, violations of the uniform fiduciaries law, negligent misrepresentation, detrimental reliance, violations of the Louisiana Securities Act and Louisiana Racketeering Act, and conspiracy. The underlying allegations in all actions relate to the purported role of SPTC in providing back-office services to Stanford Trust Company. The petitions allege that SEI and SPTC aided and abetted or otherwise participated in the sale of “certificates of deposit” issued by Stanford International Bank.

The case filed in Ascension Parish was removed to federal court and transferred by the Judicial Panel on Multidistrict Litigation to the United States District Court for the Northern District of Texas. The schedule for responding to that petition has not yet been established.

The plaintiffs in two of the cases filed in East Baton Rouge have granted SEI and SPTC an indefinite extension to respond to the petitions.

In a third East Baton Rouge action, brought as a class action, SEI and SPTC filed exceptions, which the Court granted in part, dismissing the claims under the Louisiana Unfair Trade Practices Act. Plaintiffs then filed a motion for class certification, and SEI and SPTC also filed a motion for summary judgment. The Court deferred the motion for summary judgment, stating that the motion would not be set for hearing until after the hearing on class certification. After the Court held a hearing on class certification, it certified a class composed of persons who purchased or renewed any Stanford International Bank certificates of deposit (SIB CDs) in Louisiana between January 1, 2007 and February 13, 2009 or any person for whom the Stanford Trust Company purchased SIB CDs in Louisiana between January 1, 2007 and February 13, 2009. SEI and SPTC filed motions for appeal from the class certification judgments. On February 1, 2013, plaintiffs filed a motion for Leave to File a First Amended and Restated Class Action Petition in which they asked the Court to allow them to amend the petition and add claims against certain of SEI's insurance carriers. On February 5, 2013, the Court granted two of the motions for appeal and the motion for leave to amend. On February 28, 2013, SEI responded to the First Amended and Restated Class Action Petition by seeking dismissal of the action. On March 11, 2013, the newly-added insurance carrier defendants removed the case to the Middle District of Louisiana. SEI notified the Judicial Panel on Multidistrict Litigation (MDL) of this case as a potential tag-along action. Plaintiffs filed a motion to remand the action to state court. On March 25, 2013, SEI filed a motion requesting that the federal court decline to adopt the state court's order regarding class certification, which the court dismissed without prejudice to renew upon a determination of the jurisdictional issue. On August 7, 2013, the MDL Panel transferred the matter against SEI to the Northern District of Texas. On October 1, 2014, SEI filed a renewed motion to dismiss in the Northern District of Texas, and on October 6, 2014, the District Court denied plaintiffs’ motion to remand. This case is now pending in the Northern District of Texas, and SEI is awaiting a ruling on its motion to dismiss.

In the two other cases filed in East Baton Rouge, brought by the same counsel who filed the class action, virtually all of the litigation to date has involved motions practice and appellate litigation regarding the existence of federal subjection matter jurisdiction under the federal Securities Litigation Uniform Standards Act (SLUSA). After the matter was removed to the United States District Court for the Northern District of Texas, that court dismissed the action under SLUSA. The Court of Appeals for the Fifth Circuit reversed that order, and the Supreme Court of the United States affirmed the Court of Appeals judgment on February 26, 2014. The matter was remanded to state court and no material activity has taken place since that date.

While the outcome of this litigation is uncertain given its early phase, SEI and SPTC believe that they have valid defenses to plaintiffs' claims and intend to defend the lawsuits vigorously. Because of the uncertainty of the make-up of the classes, the specific theories of liability that may survive a motion for summary judgment or other dispositive motion, the lack of discovery regarding damages, causation, mitigation and other aspects that may ultimately bear upon loss, the Company is not reasonably able to provide an estimate of loss, if any, with respect to the foregoing lawsuits.

A lawsuit entitled Steven Curd and Rebel Curd v. SEI Investments Management Corporation was filed against SIMC in the United States District Court for the Eastern District of Pennsylvania on December 11, 2013. On August 28, 2014, the Court granted SIMC’s motion to dismiss the initial complaint in the lawsuit, but also granted plaintiffs leave to amend the complaint. On October 2, 2014, plaintiffs filed an amended complaint. In the amended complaint, SEI Investments Global Funds Services (SGFS) was added as a defendant. The plaintiffs bring the case as a shareholder derivative action against SIMC and SGFS on behalf of certain SEI funds. The claims are based on Section 36(b) of the Investment Company Act of 1940, as amended, which allows shareholders of a mutual fund to sue the investment adviser of the fund or its affiliates for an alleged breach of fiduciary duty with respect to compensation received by the adviser or its affiliates. The plaintiffs have brought the suit against SIMC and SGFS with respect to five specific SEI Funds: the High Yield Bond, Tax-Managed Large Cap, and Tax-Managed Small/Mid Cap Funds, each of which is a series of the SEI Institutional Managed Trust, the Intermediate Term Municipal Fund, which is a series of the SEI Tax Exempt Trust, and the International Equity Fund, which is a series of the SEI Institutional International Trust (the SEI Funds). The plaintiffs seek: (1) damages for the SEI Funds in the amount of the alleged “excessive” fees earned by SIMC and SGFS beginning from the one year period prior to the filing of the lawsuit, plus interest, costs, and fees; (2) orders declaring that SIMC and SGFS allegedly violated Section 36(b) and enjoining SIMC and SGFS from further alleged violations; and (3) rescission of SIMC’s and SGFS’s contracts with the funds, and restitution of all allegedly excessive fees paid beginning from the one year period prior to the filing of the lawsuit, plus interest, costs, and fees. On November 24, 2014, SIMC and SGFS filed a motion to dismiss the amended complaint. The court has not yet ruled on that motion. While the outcome of this litigation is uncertain given its early phase, SIMC and SGFS believe that they have valid defenses to plaintiffs' claims and intend to defend the lawsuit vigorously, and SIMC and SGFS are not reasonably able to provide an estimate of the ultimate loss, if any, with respect to this lawsuit.

On November 26, 2014, a Writ of Summons was issued to two of our subsidiaries, SEI Investments - Global Fund Services Limited (GFSL) and SEI Investments - Trustee & Custodial Services (Ireland) Limited (T&C), to appear before the Court of First Instance Antwerp, Belgium on March 11, 2015. The plaintiffs in this case allege that through their initial investments in collective investment funds domiciled in Netherlands and subsequent transfer of claim rights to a Belgium domiciled partnership, they are beneficial owners of a portfolio of life settlement policies (the Portfolio) which lapsed due to a failure to make premium payments. The plaintiffs seek to recover jointly and severally from nine defendants including GFSL and T&C, damages of approximately $84 million. GFSL and T&C’s involvement in the litigation appears to arise out of their historical provision of administration and custody services respectively, to the Strategic Life Settlement Fund PLC , who, together with its managers, appear to be the principal defendants in this claim. While the outcome of this action is uncertain given its early phase and the lack of specific theories of liability asserted against GFSL and T&C, each of GFSL and T&C believe that they have valid defenses to plaintiffs’ claims and intend to defend the lawsuit vigorously.

- Definition

The entire disclosure for commitments and contingencies.

+ References+ Details

Income Taxes

12 Months Ended

Dec. 31, 2014

Income Tax Disclosure [Abstract]

Income Taxes

The federal and state and foreign income tax provision is summarized as follows:



Year Ended December 31,	2014		2013			2012
Current
Federal	$	155,273	$	153,856		$	112,247
State	8,744		11,542			5,284
Foreign	5,254		4,727			4,511
	169,271		170,125			122,042
Deferred, including current deferred
Federal	1,667		(2,214		)	(2,708		)
State	11		(16,264		)	(2,199		)
Foreign	—		(4,814		)	3,970
	1,678		(23,292		)	(937		)
Income taxes attributable to the noncontrolling interest	—		91			357
Total income taxes	$	170,949	$	146,924		$	121,462

Annual tax provisions include amounts considered sufficient to pay assessments that may result from examination of prior year tax returns; however, the amount ultimately paid upon resolution of issues raised may differ materially from the amount accrued. The examination and the resolution process may last longer than one year.

The components of Income before income taxes are summarized as follows:



Year Ended December 31,	2014		2013		2012
Domestic	$	475,175	$	427,915	$	319,907
Foreign	14,487		7,042		8,046
	$	489,662	$	434,957	$	327,953

The effective income tax rate differs from the federal income tax statutory rate due to the following:



Year Ended December 31,	2014		2013		2012
Statutory rate	35.0	%	35.0	%	35.0	%
State taxes, net of Federal tax benefit	1.2		1.5		1.0
Foreign tax expense and tax rate differential	(0.7	)	0.5		1.6
Research and development tax credit	(0.4	)	(0.8	)	—
Domestic Production Activities Deduction	(0.4	)	(0.5	)	(0.6	)
PA Tax Law changes and change in valuation allowance on loss carryforwards	—		(2.4	)	(0.3	)
Net change in uncertain tax positions	0.3		0.1		0.5
Other, net	(0.1	)	0.3		(0.3	)
	34.9	%	33.7	%	36.9	%

The impact on the Company's effective income tax rate from the net change in uncertain tax positions in 2014 relates to federal issues mainly associated with the compilation of foreign tax credits and state tax issues. For 2013 and 2012, the impact from the net change in uncertain tax positions relates to federal and state tax issues and foreign tax issues.

Undistributed earnings of the Company’s foreign subsidiaries amounted to approximately $61,833 at December 31, 2014. Those earnings are considered to be indefinitely reinvested and, accordingly, no U.S. federal and state income taxes have been provided thereon. Upon distribution of those earnings, in the form of dividends or otherwise, the Company would be subject to both U.S. income taxes, subject to an adjustment for foreign tax credits, and withholding taxes payable to the various foreign countries. Determination of the amount of unrecognized deferred U.S. income tax liability is not practicable because of the complexities associated with its hypothetical calculation, including the availability, or lack thereof, of foreign tax credits to reduce a portion of the U.S. liability.

Deferred income taxes for 2014, 2013 and 2012 reflect the impact of temporary differences between the amount of assets and liabilities for financial reporting purposes and such amounts as measured by tax laws and regulations. In 2013, the Company's deferred income tax net liability decreased significantly due to the following: (1) Pennsylvania Tax Law changes enacted on July 18, 2013 which became effective on January 1, 2014. These changes reduced the deferred tax liability which had accumulated during prior years. In accordance with the tax accounting rules, the effect of the law change is recorded in the year in which the law was signed. The primary change that affects the Company results from the reduction of net income apportioned to the State of Pennsylvania. The bill adopts “market-based” sourcing for apportionment. This method apportions sales to the state where the benefits are being derived by the customer. The current method apportions sales of services to the state where the cost was incurred to perform those services; (2) the Company's current payable was increased by unfavorable temporary differences such as stock option compensation which is not currently deductible but will reverse in the future; thus reducing the Company's deferred tax liability; (3) the Company's current payable decreased as a result of the sale of SEI AK.

The net deferred income tax liability is comprised of:



Year Ended December 31,	2014			2013
Current deferred income taxes:
Gross assets	$	2,952		$	2,458
Gross liabilities	(4,366		)	(4,111		)
	(1,414		)	(1,653		)
Valuation allowance	—			—
	(1,414		)	(1,653		)
Long-term deferred income taxes:
Gross assets	66,335			69,483
Gross liabilities	(113,581		)	(121,317		)
	(47,246		)	(51,834		)
Valuation allowance	(16,509		)	(14,738		)
	(63,755		)	(66,572		)
Net deferred income tax liability	$	(65,169	)	$	(68,225	)

The valuation allowances against deferred tax assets at December 31, 2014 and 2013 are related to state net operating losses from certain domestic subsidiaries. Certain state tax statutes significantly limit the utilization of net operating losses for domestic subsidiaries. Furthermore, these net operating losses cannot be used to offset the net income of other subsidiaries. In 2014, the valuation also includes valuation of foreign tax credit.

The tax effect of significant temporary differences representing deferred tax liabilities is:



Year Ended December 31,	2014			2013
Difference in financial reporting and income tax depreciation methods	$	(3,637	)	$	(7,043	)
Reserves not currently deductible	209			235
Capitalized software currently deductible for tax purposes, net of amortization	(118,841		)	(119,800		)
State deferred income taxes	(420		)	251
Revenue and expense recognized in different periods for financial reporting and income tax purposes	6,212			3,856
Unrealized holding gain on investments	(475		)	(308		)
Stock-based compensation expense	38,989			45,555
State net operating loss carryforward	24,150			21,215
Valuation allowance on deferred tax assets	(16,509		)	(14,738		)
Federal benefit of state tax deduction for uncertain tax positions	2,913			2,643
Foreign tax credit	2,327			—
Foreign deferred including taxes on cumulative undistributed earnings of SEI AK	(87		)	(91		)
Net deferred income tax liability	$	(65,169	)	$	(68,225	)

The Company recognizes uncertain tax positions in accordance with the applicable accounting guidance and adjusts these liabilities when management’s judgment changes as a result of the evaluation of new information not previously available. Due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from our current estimate of the tax liabilities. The Company’s total unrecognized tax benefit, not including interest and penalties, as of December 31, 2014 was $14,018, of which $12,162 would affect the effective tax rate if the Company were to recognize the tax benefit. The gross amount of uncertain tax liability of $4,757 which is expected to be paid within one year is netted against the current payable account while the remaining amount of $10,327 is included in Other long-term liabilities on the accompanying Consolidated Balance Sheets. During the year ended December 31, 2014, the Company recognized $1,336 of previously unrecognized tax benefits relating to the lapse of the statute of limitation for certain state filings.

The Company files a consolidated federal income tax return and separate income tax returns with various states. Certain subsidiaries of the Company file tax returns in foreign jurisdictions. The Company is no longer subject to U.S. federal income tax examination for years before 2011 and is no longer subject to state, local or foreign income tax examinations by authorities for years before 2010.

A reconciliation of the beginning and ending amount of unrecognized tax benefit is as follows:



	2014			2013			2012
Balance as of January 1	$	12,028		$	11,553		$	9,410
Tax positions related to current year:
Gross additions	1,957			1,834			2,196
Gross reductions	—			—			—
	1,957			1,834			2,196
Tax positions related to prior years:
Gross additions	1,369			3,435			1,990
Gross reductions	—			—			—
	1,369			3,435			1,990
Settlements	—			(3,772		)	(99		)
Lapses on statute of limitations	(1,336		)	(1,022		)	(1,944		)
Balance as of December 31	$	14,018		$	12,028		$	11,553

The above reconciliation of the gross unrecognized tax benefit will differ from the amount which would affect the effective tax rate because of the recognition of the federal and state tax benefits.

The Company classifies all interest and penalties as income tax expense. The Company has recorded $1,066, $754 and $770 in liabilities for tax related interest and penalties in 2014, 2013 and 2012, respectively.

The Company estimates it will recognize $1,700 of unrecognized tax benefits within the next twelve months due to lapses on the statute of limitation.

The Company includes its direct and indirect subsidiaries in its U.S. consolidated federal income tax return. The Company’s tax sharing allocation agreement provides that any subsidiary having taxable income will pay a tax liability equivalent to what that subsidiary would have paid if it filed a separate income tax return. If the separately calculated federal income tax provision for any subsidiary results in a tax loss, the current benefit resulting from such loss, to the extent utilizable on a separate return basis, is accrued and paid to that subsidiary.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References+ Details

Business Segment Information

12 Months Ended

Dec. 31, 2014

Segment Reporting [Abstract]

Business Segment Information

The Company’s reportable business segments are:

Private Banks – provides investment processing and investment management programs to banks and trust institutions, independent wealth advisers and financial advisors worldwide;

Investment Advisors – provides investment management programs to affluent investors through a network of independent registered investment advisors, financial planners and other investment professionals in the United States;

Institutional Investors – provides investment management programs and administrative outsourcing solutions to retirement plan sponsors, hospitals and not-for-profit organizations worldwide;

Investment Managers – provides investment operations outsourcing solutions to fund companies, banking institutions and both traditional and non-traditional investment managers worldwide; and

Investments in New Businesses – focuses on providing investment management programs to ultra-high-net-worth families residing in the United States; developing internet-based investment services and advice solutions; entering new markets; and conducting other research and development activities.

In 2014, 2013 and 2012, no single customer accounted for more than ten percent of revenues in any business segment.

The following tables highlight certain financial information about each of the Company’s business segments for the years ended December 31, 2014, 2013 and 2012:



	Private Banks		Investment Advisors		Institutional Investors		Investment Managers		Investments In New Businesses			Total
	For the Year Ended December 31, 2014
Revenues	$	441,467	$	283,811	$	284,677	$	251,310	$	4,740		$	1,266,005
Expenses	399,620		146,500		140,659		159,176		18,377			864,332
Operating profit (loss)	$	41,847	$	137,311	$	144,018	$	92,134	$	(13,637	)	$	401,673
Gain on sale of subsidiary	5,582		—		—		—		—			5,582
Total profit (loss)	$	47,429	$	137,311	$	144,018	$	92,134	$	(13,637	)	$	407,255



	Private Banks		Investment Advisors		Institutional Investors		Investment Managers		Investments In New Businesses			Total
	For the Year Ended December 31, 2013
Revenues	$	397,138	$	241,252	$	257,658	$	226,081	$	4,003		$	1,126,132
Expenses	392,399		133,962		133,218		148,977		15,723			824,279
Operating profit (loss)	$	4,739	$	107,290	$	124,440	$	77,104	$	(11,720	)	$	301,853
Gain on sale of subsidiary	22,112		—		—		—		—			22,112
Total profit (loss)	$	26,851	$	107,290	$	124,440	$	77,104	$	(11,720	)	$	323,965



	Private Banks		Investment Advisors		Institutional Investors		Investment Managers		Investments In New Businesses			Total
	For the Year Ended December 31, 2012
Revenues	$	364,788	$	202,703	$	227,889	$	193,484	$	3,658		$	992,522
Expenses	357,001		120,146		116,546		127,525		14,954			736,172
Operating profit (loss)	$	7,787	$	82,557	$	111,343	$	65,959	$	(11,296	)	$	256,350

A reconciliation of the total reported for the business segments to income from operations in the Consolidated Statements of Operations for the years ended December 31, 2014, 2013 and 2012 is as follows:



Year Ended December 31,	2014			2013			2012
Total operating profit from segments above	$	401,673		$	301,853		$	256,350
Corporate overhead expenses	(48,889		)	(53,733		)	(45,759		)
Noncontrolling interest reflected in segments	—			289			975
Income from operations	$	352,784		$	248,409		$	211,566

The following tables provide additional information for the years ended December 31, 2014, 2013 and 2012 pertaining to our business segments:



	Capital Expenditures (1)						Depreciation
Year Ended December 31,	2014		2013		2012		2014		2013		2012
Private Banks	$	30,883	$	34,258	$	32,509	$	13,393	$	15,506	$	15,226
Investment Advisors	13,783		12,611		11,193		2,507		2,091		1,981
Institutional Investors	4,575		2,712		2,781		1,041		893		1,012
Investment Managers	9,505		4,871		5,494		2,917		1,970		1,914
Investments in New Businesses	2,547		639		632		1,983		1,589		1,716
Total from business segments	$	61,293	$	55,091	$	52,609	$	21,841	$	22,049	$	21,849
Corporate Overhead	2,053		760		1,465		607		448		737
	$	63,346	$	55,851	$	54,074	$	22,448	$	22,497	$	22,586

(1) Capital expenditures include additions to property and equipment and capitalized software.



	Amortization
Year Ended December 31,	2014		2013		2012
Private Banks	$	24,993	$	22,379	$	22,218
Investment Advisors	9,228		8,234		7,167
Institutional Investors	1,430		1,274		1,208
Investment Managers	954		851		804
Investments in New Businesses	1,846		1,636		1,249
Total from business segments	$	38,451	$	34,374	$	32,646
Corporate Overhead	228		228		612
	$	38,679	$	34,602	$	33,258



	Total Assets
	2014		2013
Private Banks	$	417,890	$	430,613
Investment Advisors	134,371		124,028
Institutional Investors	118,397		97,816
Investment Managers	134,614		122,969
Investments in New Businesses	21,830		6,064
Total from business segments	$	827,102	$	781,490
Corporate Overhead (2)	715,773		657,679
	$	1,542,875	$	1,439,169

(2) Unallocated assets primarily consist of cash and cash equivalents, marketable securities, and certain other shared services assets.

The following table presents revenues based on the location of the use of the products or services:



For the Year Ended December 31,	2014		2013		2012
United States	$	1,063,223	$	962,266	$	843,407
International operations	202,782		163,866		149,115
	$	1,266,005	$	1,126,132	$	992,522

The following table presents assets based on their location:



	2014		2013
United States	$	1,315,036	$	1,231,565
International operations	227,839		207,604
	$	1,542,875	$	1,439,169

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

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+ Details

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The Company, either by itself or through its wholly-owned subsidiaries, is a party to Investment Advisory and Administration Agreements with regulated investment companies (RICs) and other investment products which are administered by the Company. These investment products are offered to clients of the Company and its subsidiaries. Under the Investment Advisory and Administration Agreements, the Company receives a fee for providing investment advisory, administrative, and accounting services. The investment advisory and administration fee is a fixed percentage, referred to as basis points, of the average daily net assets, subject to certain limitations. Investment advisory and administration fees received by the Company totaled $489,066, $422,825 and $380,645 in 2014, 2013 and 2012, respectively. The Company is also a party to various agreements with several RICs which are advised and/or administered by the Company. The Company receives a fee for providing shareholder, administrative and distribution services pursuant to the provisions of various shareholder service, administrative service, and distribution plans adopted by the RICs. These fees totaled $66,424, $47,988 and $37,827 in 2014, 2013 and 2012, respectively. A portion of the transaction costs incurred by the RICs for securities transactions are directed to the Company’s broker-dealer subsidiary in its capacity as an introducing broker-dealer. The Company recognized $1,733, $620 and $1,213 in commissions during 2014, 2013 and 2012, respectively. Receivables from regulated investment companies on the accompanying Consolidated Balance Sheets primarily represent fees receivable for distribution, investment advisory, and administration services to various RICs sponsored by SEI.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References+ Details

Sale of SEI Asset Korea

12 Months Ended

Dec. 31, 2014

Discontinued Operations and Disposal Groups [Abstract]

Sale of SEI Asset Korea

On July 31, 2012, the Company, MetLife International Holdings, Inc. (MetLife) and International Finance Corporation (IFC) entered into a definitive agreement with Baring Asset Management Limited (Barings) to sell all ownership interest in SEI Asset Korea (SEI AK). SEI AK was located in South Korea and provided domestic equity and fixed income investment management services to financial institutions and pension funds.

On March 28, 2013, all conditions subject to closing the transaction were satisfied and all ownership interests in SEI AK were transferred to Barings. The net working capital of SEI AK at closing in excess of required regulatory capital, and subject to certain other adjustments, was distributed to the Company, MetLife and IFC in accordance with the ownership interests. The Company recognized a pre-tax gain of $22,112, or $0.08 diluted earnings per share, during 2013. Under the terms of the agreement, a portion of the purchase price was paid upon closing with up to an additional $11,220 payable to the Company as a contingent purchase price with respect to three one-year periods ending on December 31, 2013, 2014 and 2015 depending upon whether SEI AK achieves specified revenue measures during such periods. The Company recognized a pre-tax gain of $5,582, or $0.02 diluted earnings per share, during 2014 with respect to the first one-year period which ended December 31, 2013. The Company's gains from the sale of SEI AK are included in Gain on sale of subsidiary on the accompanying Consolidated Statement of Operations.

The operating results of SEI AK were included in the Private Banks business segment. SEI AK revenues and net income included in the Company's Consolidated Statement of Operations were as follows:



	For the Period January 1, 2013 through March 28, 2013


				2012
Revenues	$	2,889		$	11,514

Net income	$	796		$	2,703
Less: Income attributable to the noncontrolling interests	(350		)	(1,186		)
Net income attributable to SEI AK	$	446		$	1,517

- Definition

The entire disclosure for the facts and circumstances leading to the completed or expected disposal, manner and timing of disposal, the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the segment in which the disposal group was reported, and the classification (whether sold or classified as held for sale) and carrying value of the assets and liabilities comprising the disposal group. Includes all disposal groups, including those classified as components of the entity (discontinued operations).

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+ Details

Settlement Agreement	12 Months Ended
Settlement Agreement	Dec. 31, 2014
Litigation Settlement [Abstract]
Settlement Agreement	On April 24, 2013, the Company entered into a Settlement Agreement with respect to litigation captioned Abu Dhabi Commercial Bank, et. al. v. Morgan Stanley & Co., Incorporated, et. al., brought by a group of plaintiffs, including the Company, related to the purchase of securities by the Company and others of Cheyne Finance LLC, a SIV security. In accordance with the Settlement Agreement, the Company received a cash settlement payment of $43,429 after fees and expenses during the three months ended June 30, 2013. The income related to the cash settlement payment is reflected in Other income on the accompanying Consolidated Statements of Operations.

Quarterly Financial Data

12 Months Ended

Dec. 31, 2014

Quarterly Financial Data [Abstract]

Quarterly Financial Data

Quarterly Financial Data (Unaudited)



	For the Three Months Ended
2014	March 31			June 30			September 30			December 31
Revenues	$	302,386		$	318,815		$	322,047		$	322,757
Income before income taxes	$	116,665		$	128,854		$	128,618		$	115,525
Net income attributable to SEI	$	74,820		$	82,813		$	83,983		$	77,097
Basic earnings per share	$	0.44		$	0.49		$	0.50		$	0.46
Diluted earnings per share	$	0.43		$	0.48		$	0.49		$	0.45

Effective income tax rate	35.9		%	35.7		%	34.7		%	33.3		%

Gain on sale of subsidiary (Note 15)	$	5,582		$	—		$	—		$	—
Diluted earnings per share (1)	$	0.02		$	—		$	—		$	—

Loss from impairment charge (Note 2)	$	—		$	—		$	—		$	11,266
Diluted earnings per share (2)	$	—		$	—		$	—		$	0.06

(1) Attributable to gain on sale of subsidiary.

(2) Attributable to loss from impairment charge.



	For the Three Months Ended
2013	March 31			June 30			September 30			December 31
Revenues	$	271,879		$	274,574		$	280,655		$	299,024
Income before income taxes	$	110,962		$	129,387		$	93,986		$	101,063
Net income attributable to SEI	$	71,920		$	83,494		$	67,195		$	65,515
Basic earnings per share	$	0.42		$	0.48		$	0.39		$	0.39
Diluted earnings per share	$	0.41		$	0.47		$	0.38		$	0.37

Effective income tax rate	34.9		%	35.5		%	28.5		%	35.2		%

Gain on sale of subsidiary (Note 15)	$	22,112		$	—		$	—		$	—
Diluted earnings per share (3)	$	0.08		$	—		$	—		$	—

Settlement agreement (Note 16)	$	—		$	43,429		$	—		$	—
Diluted earnings per share (4)	$	—		$	0.16		$	—		$	—

(3) Attributable to gain on sale of subsidiary.

(4) Attributable to settlement agreement.

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References+ Details

Schedule II - Valuation And Qualifying Accounts And Reserves

12 Months Ended

Dec. 31, 2014

Valuation and Qualifying Accounts [Abstract]

Schedule II - Valuation and Qualifying Accounts and Reserves



Year Ended December 31,			Additions
Description	Balance at Beginning of Year		Charged to Costs and Expenses			Charged to Other Accounts		(Deductions)			Balance at End of Year
Allowance for doubtful accounts:
2014	$	651	$	133		$	—	$	—		$	784
2013	805		—			—		(154		)	651
2012	924		—			—		(119		)	805
Deferred income tax valuation allowance:
2014	$	14,738	$	—		$	1,771	$	—		$	16,509
2013	6,879		(485		)	8,344		—			14,738
2012	8,585		(1,706		)	—		—			6,879

Summary of Significant Accounting Policies (Policy)	12 Months Ended
Summary of Significant Accounting Policies (Policy)	Dec. 31, 2014
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries and entities in which it holds a controlling financial interest. The Company determines whether it has a controlling financial interest either by its decision-making ability through voting interests or by the extent of the Company’s participation in the economic risks and rewards of the entity through variable interests. The Company’s principal subsidiaries are SEI Investments Distribution Co. (SIDCO), SEI Investments Management Corporation (SIMC), SEI Private Trust Company (SPTC), SEI Trust Company (STC), SEI Global Services, Inc. (SGSI) and SEI Investments (Europe) Limited (SIEL). All intercompany accounts and transactions have been eliminated. The Company accounts for investments in unconsolidated entities that are 20 percent to 50 percent owned or are 20 percent or less owned and have the ability to exercise significant influence over the operating and financial policies of the entity under the equity method of accounting. Under this method of accounting, the Company’s interest in the net assets of unconsolidated entities is reflected in Investment in unconsolidated affiliates on the accompanying Consolidated Balance Sheet and its interest in the earnings or losses of unconsolidated entities is reflected in Equity in earnings of unconsolidated affiliates on the accompanying Consolidated Statement of Operations.
Variable Interest Entities	Variable Interest Entities The Company has involvement with various variable interest entities (VIE or VIEs). These VIEs consist of LSV Employee Group III, LLC (LSV Employee Group III) and investment products established for clients created in the form of various types of legal entity structures. According to the most recent accounting guidance issued by the Financial Accounting Standards Board (FASB), the determination of whether a company is required to consolidate an entity is based on, among other things, an entity’s purpose and design, a company’s ability to direct the activities of the entity that most significantly impact the entity’s economic performance, and whether a company is obligated to absorb losses or receive benefits that could be potentially significant to the entity. The guidance requires ongoing reassessments of whether an enterprise is the primary beneficiary of a VIE and requires disclosures about an enterprises involvement in VIEs. The FASB deferred the accounting guidance for certain types of investment entities. The deferral allows asset managers that have no obligation to fund potentially significant losses of an investment entity to continue to apply the previous guidance to investment entities that have attributes of entities defined in the “Investment Company Guide.” The deferral applies to many mutual funds, hedge funds, private equity funds, venture capital and certain other types of entities. Also, money market funds subject to rule 2a-7 of the Investment Company Act of 1940 qualify for deferral. However, the deferral does not apply to the new disclosure requirements. All of the Company’s investment products where the Company is the sponsor and/or investment manager that are VIEs qualify for the deferral; therefore, the Company will continue to apply the previous guidance for the consolidation of VIEs (See Note 3).
Management's Use of Estimates	Management’s Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Revenue Recognition	Revenue Recognition The Company’s principal sources of revenues are: (1) asset management, administration and distribution fees earned based upon a contractual percentage of net assets under management or administration; (2) information processing and software servicing fees that are either recurring and primarily earned based upon the number of trust accounts being serviced or non-recurring and based upon project-oriented contractual agreements related to client implementations; and (3) transaction-based fees for providing trade-execution services. The Company’s revenues are based on contractual arrangements. Revenues are recognized in the periods in which the related services are performed provided that persuasive evidence of an agreement exists, the fee is fixed or determinable, and collectibility is reasonably assured. Cash received by the Company in advance of the performance of services is deferred and recognized as revenue when earned. Reimbursements received for out-of-pocket expenses incurred are recorded as revenue. Certain portions of the Company’s revenues require management’s consideration of the nature of the client relationship in determining whether to recognize as revenue the gross amount billed or net amount retained after payments are made to suppliers for certain services related to the product or service offering.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers investment instruments purchased with an original maturity of three months or less to be cash equivalents.
Allowance for Doubtful Accounts	Allowances for Doubtful Accounts The Company provides an allowance for doubtful accounts equal to the estimated uncollectible amounts. The Company’s estimate is based on historical collection experience and a review of the current status of trade accounts receivable.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments which potentially expose the Company to concentrations of credit risk consist primarily of cash equivalents and trade receivables. Cash equivalents are principally invested in short-term money market funds or placed with major banks and high-credit qualified financial institutions. Cash deposits maintained with institutions are in excess of federally insured limits. Concentrations of credit risk with respect to our receivables are limited due to the large number of clients and their dispersion across geographic areas. No single group or customer represents greater than ten percent of total accounts receivable.
Property and Equipment	Property and Equipment Property and Equipment are recorded at cost. Expenditures for major additions and improvements are capitalized and minor replacements, maintenance, and repairs are charged to expense as incurred. Construction in progress includes the cost of construction and other direct costs attributable to the construction. When property and equipment are retired or disposed of, the related cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the results of operations for the respective period. Depreciation is provided over the estimated useful lives using the straight line method for financial statement purposes. No provision for depreciation is made for construction in progress until such time as the relevant assets are completed and put into service. The Company uses other depreciation methods, generally accelerated, for tax purposes where appropriate. Buildings and building improvements are depreciated over 25 to 39 years. Equipment, purchased software and furniture and fixtures have useful lives ranging from 3 to 5 years. Amortization of leasehold improvements is computed using the straight line method over the shorter of the remaining lease term or the estimated useful lives of the improvements.
Marketable Securities	Marketable Securities The classification of investments in marketable securities is determined at the time of purchase and reevaluated at each balance sheet date. Debt and equity securities classified as available-for-sale are reported at fair value as determined by the most recently traded price of each security at the balance sheet date. Unrealized gains and losses, net of income taxes, are reported as a separate component of comprehensive income. SIDCO, the Company’s broker-dealer subsidiary, reports changes in fair value of marketable securities through current period earnings due to specialized accounting practices related to investments by broker-dealers. The Company records its investments in funds sponsored by LSV on the accompanying Consolidated Balance Sheets at fair value. Unrealized gains and losses from the change in fair value of these securities are recognized in current period earnings. The specific identification method is used to compute the realized gains and losses on all of the Company’s marketable securities (See Note 6). The Company evaluates the realizable value of its marketable securities on a quarterly basis. In the event that the carrying value of an investment exceeds its fair value and the decline in value is determined to be other-than-temporary, an impairment charge is recorded and a new cost basis for the investment is established. Some of the factors considered in determining other-than-temporary impairment for equity securities include, but are not limited to, significant or prolonged declines in the fair value of the investments, the Company’s ability and intent to retain the investment for a period sufficient to allow the value to recover, and the financial condition of the investment. Some of the factors considered in determining other-than-temporary impairment for debt securities include, but are not limited to, the intent of management to sell the security, the likelihood that the Company will be required to sell the security before recovering its cost, and management’s expectation to recover the entire amortized cost basis of the security even if there is no intent to sell the security.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The fair value hierarchy describes three levels of inputs that may be used by the Company to measure fair value: Level 1 – Quoted prices in active markets for identical assets or liabilities without adjustment. The Company’s Level 1 assets primarily include investments in mutual funds sponsored by SEI that are quoted daily. Level 2 – Observable inputs other than Level 1 prices, such as quoted prices for similar assets, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 financial assets consist of Government National Mortgage Association (GNMA) mortgage-backed securities, Federal Home Loan Bank (FHLB) and other U.S. government agency short-term notes and investment grade commercial paper, and investment funds sponsored by LSV. The investments in GNMA mortgage-backed securities were purchased for the sole purpose of satisfying applicable regulatory requirements imposed on our wholly-owned limited purpose federal thrift subsidiary, SPTC. The investments in FHLB and other U.S. government agency short-term notes and investment grade commercial paper were purchased as part of a cash management program requiring only short term, top-tier investment grade government and corporate securities. The investment funds sponsored by LSV primarily invest in equity securities of non-U.S. developed nations which are traded in active markets. Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment by management. The Company had no Level 3 financial assets at December 31, 2014 or 2013. The fair value of an asset or liability may include inputs from more than one level in the fair value hierarchy. The lowest level of significant inputs used to value the asset or liability determines which level the asset or liability is classified in its entirety. Transfers between levels of the fair value hierarchy are reported at fair value as of the beginning of the period in which the transfers occur.
Capitalized Software	Capitalized Software Costs incurred for the development of internal use software to be offered in a hosting arrangement is capitalized during the development stage of the software application. These costs include direct external and internal costs to design the software configuration and interfaces, coding, installation, and testing. Costs incurred during the preliminary and post-implementation stages of the software application are expensed as incurred. Costs associated with significant enhancements to a software application are capitalized while costs incurred to maintain existing software applications are expensed as incurred. The capitalization of software development costs requires considerable judgment by management with respect to certain external factors, including, but not limited to, technological and economic feasibility, and estimated economic life. Amortization of capitalized software development costs begins when the product is ready for its intended use. Capitalized software development costs are amortized on a product-by-product basis using the straight-line method over the estimated economic life of the product or enhancement. The Company's capitalized software development costs primarily relate to the further development of the SEI Wealth Platform^SM(the Platform). The initial version of the Platform was placed into service in July 2007. Further enhancements and upgrades will continue to occur. As of December 31, 2014, the net book value of the Platform was $309,040. The Company capitalized $34,877, $39,500 and $31,004 of software development costs during 2014, 2013 and 2012, respectively. Included in the amount for 2013 is a one-time contractual payment of $8,812 to exercise a conversion option in lieu of periodic fee payments pertaining to a software license for functionality utilized by the Platform. The Platform has an estimated useful life of 15 years and a weighted average remaining life of 7.5 years. Amortization expense for the Platform was $38,357, $34,045 and $32,177 in 2014, 2013 and 2012, respectively, and is included in Amortization expense on the accompanying Consolidated Statements of Operations. During 2012, the Company decided to discontinue the use of specific functionality within the Platform and expensed the remaining net book value of $2,661 related to previously capitalized software development costs of the component. This cost is included in total amortization expense on the accompanying Consolidated Statements of Operations. The Company evaluates the carrying value of capitalized software development costs when circumstances indicate the carrying value may not be recoverable. The review of capitalized software development costs for impairment requires significant assumptions about operating strategies, underlying technologies utilized, and external market factors. External market factors include, but are not limited to, expected levels of competition, barriers to entry by potential competitors, stability in the target market and governmental regulations.
Income Taxes	Income Taxes The Company applies the asset and liability approach to account for income taxes whereby deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The components of the deferred tax assets and liabilities are individually classified as current and non-current based on their characteristics.
Foreign Currency Translation	Foreign Currency Translation The assets and liabilities and results of operations of the Company’s foreign subsidiaries are measured using the foreign subsidiary’s local currency as the functional currency. Assets and liabilities have been translated into U.S. dollars using the rates of exchange at the balance sheet dates. The results of operations have been translated into U.S. dollars at average exchange rates prevailing during the period. The resulting translation gain and loss adjustments are recorded as a separate component of comprehensive income. Transaction gains and losses from exchange rate fluctuations are included in the results of operations in the periods in which they occur.
Earnings Per Share	Earnings Per Common Share Basic earnings per common share is computed by dividing net income attributable to SEI Investments common shareholders by the weighted average number of common shares outstanding during the period. Diluted earnings per common share is computed by dividing net income attributable to SEI Investments common shareholders by the combination of the weighted average number of common shares outstanding and the dilutive potential common shares, such as stock options, outstanding during the period.
Stock-based Compensation	Stock-Based Compensation Stock-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense over the requisite service period, which is the vesting period. The Company uses historical data to estimate pre-vesting forfeitures and record stock-based compensation expense only for those awards that are expected to vest. The amount of stock-based compensation expense that is recognized in a given period is dependent upon management’s estimate of when the vesting targets are expected to be achieved. If this estimate proves to be inaccurate, the remaining amount of stock-based compensation expense could be accelerated, spread out over a longer period, or reversed
New Accounting Pronouncements	New Accounting Pronouncements On May 28, 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (ASU 2014-09), requiring an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. The updated standard permits the use of either the retrospective or cumulative effect transition method. Early adoption is not permitted. ASU 2014-09 becomes effective for the Company during the first quarter 2017. The Company is currently evaluating the transition method that will be elected and the effect that the updated standard will have on its consolidated financial statements and related disclosures. On February 18, 2015, the FASB issued Accounting Standards Update No. 2015-02, Consolidation (Topic 810) - Amendments to the Consolidation Analysis (ASU 2015-02). The new guidance applies to entities in all industries and provides a new scope exception to registered money market funds and similar unregistered money market funds. It makes targeted amendments to the current consolidation guidance and ends the deferral granted to investment companies from applying the VIE guidance. ASU 2015-02 becomes effective for the Company during the first quarter 2016. The Company is currently evaluating the effect that the standard will have on its consolidated financial statements and related disclosures.
Reclassifications	Reclassifications Certain prior year amounts have been reclassified to conform to current year presentation.
Investments in Equity Method Investments	The Company accounts for its interest in LSV using the equity method because of its less than 50 percent ownership. The Company’s interest in the net assets of LSV is reflected in Investment in unconsolidated affiliates on the accompanying Consolidated Balance Sheets and its interest in the earnings of LSV is reflected in Equity in earnings of unconsolidated affiliates on the accompanying Consolidated Statements of Operations. The Company accounts for its interest in Gao Fu using the equity method. As of December 31, 2014, the Company owns approximately 27.6 percent of the outstanding voting stock of Gao Fu. The Company's interest in the net assets of Gao Fu is reflected in Investment in unconsolidated affiliates on the accompanying Consolidated Balance Sheets and its interest in the gains and losses of Gao Fu is reflected in Equity in earnings of unconsolidated affiliates on the accompanying Consolidated Statements of Operations.
Investments in Affiliated Funds	As a practical expedient, the Company relies on the net asset values (NAVs) of the investment funds sponsored by LSV as the fair value. The NAVs of the funds are calculated by the funds' independent custodian and are derived from the fair values of the underlying investments as of the reporting date.
Securities Owned	The Company’s broker-dealer subsidiary, SIDCO, has investments in U.S. government agency and commercial paper securities with maturity dates less than one year. These investments are reflected as Securities owned on the accompanying Consolidated Balance Sheets. Due to specialized accounting practices applicable to investments by broker-dealers, the securities are reported at fair value and changes in fair value are recorded in current period earnings.
Unremitted Earnings in Foreign Investment	Those earnings are considered to be indefinitely reinvested and, accordingly, no U.S. federal and state income taxes have been provided thereon. Upon distribution of those earnings, in the form of dividends or otherwise, the Company would be subject to both U.S. income taxes, subject to an adjustment for foreign tax credits, and withholding taxes payable to the various foreign countries. Determination of the amount of unrecognized deferred U.S. income tax liability is not practicable because of the complexities associated with its hypothetical calculation, including the availability, or lack thereof, of foreign tax credits to reduce a portion of the U.S. liability.
Uncertain Tax Positions	The Company recognizes uncertain tax positions in accordance with the applicable accounting guidance and adjusts these liabilities when management’s judgment changes as a result of the evaluation of new information not previously available. Due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from our current estimate of the tax liabilities.

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Calculation Of Basic And Diluted Earnings Per Share

The calculations of basic and diluted earnings per share for 2014, 2013 and 2012 are:



	For the Year Ended December 31, 2014
	Net income attributable to SEI (Numerator)		Shares (Denominator)	Per-Share Amount
Basic earnings per common share	$	318,713	168,246,000	$	1.89
Dilutive effect of stock options	—		4,319,000
Diluted earnings per common share	$	318,713	172,565,000	$	1.85



	For the Year Ended December 31, 2013
	Net income attributable to SEI (Numerator)		Shares (Denominator)	Per-Share Amount
Basic earnings per common share	$	288,124	171,561,000	$	1.68
Dilutive effect of stock options	—		4,157,000
Diluted earnings per common share	$	288,124	175,718,000	$	1.64



	For the Year Ended December 31, 2012
	Net income attributable to SEI (Numerator)		Shares (Denominator)	Per-Share Amount
Basic earnings per common share	$	206,848	174,295,000	$	1.19
Dilutive effect of stock options	—		1,577,000
Diluted earnings per common share	$	206,848	175,872,000	$	1.18

Composition of Certain Financial Statement Captions (Tables)

12 Months Ended

Dec. 31, 2014

Items Included in Consolidated Statement of Financial Condition [Abstract]

Receivables

Receivables on the accompanying Consolidated Balance Sheets consist of:



	2014			2013
Trade receivables	$	48,394		$	44,502
Fees earned, not billed	139,038			128,248
Other receivables	7,771			14,565
	195,203			187,315
Less: Allowance for doubtful accounts	(784		)	(651		)
Receivables, net	$	194,419		$	186,664

Property And Equipment

Property and Equipment on the accompanying Consolidated Balance Sheets consists of:



	2014			2013
Buildings	$	149,890		$	138,426
Equipment	78,266			70,117
Land	9,997			9,929
Purchased software	104,964			96,268
Furniture and fixtures	16,944			17,060
Leasehold improvements	5,675			4,670
Construction in progress	1,094			2,589
	366,830			339,059
Less: Accumulated depreciation	(241,295		)	(220,064		)
Property and Equipment, net	$	125,535		$	118,995

Accrued Liabilities

Accrued Liabilities on the accompanying Consolidated Balance Sheets consist of:



	2014		2013
Accrued employee compensation	$	73,269	$	69,256
Accrued employee benefits and other personnel	6,482		9,647
Accrued consulting, outsourcing and professional fees	18,915		19,311
Accrued sub-advisory, distribution and other asset management fees	31,913		25,018
Accrued dividend payable	40,178		37,314
Other accrued liabilities	36,672		27,577
Accrued liabilities	$	207,429	$	188,123

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Fair Value Of Certain Financial Assets And Liabilities

The fair value of certain financial assets and liabilities of the Company was determined using the following inputs:



	December 31, 2014
	Fair Value Measurements at Reporting Date Using
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Assets
Equity available-for-sale securities	$	11,588	$	11,588	$	—
Fixed-income available-for-sale securities	66,021		—		66,021
Fixed income securities owned	21,175		—		21,175
Investment funds sponsored by LSV	4,523		—		4,523
	$	103,307	$	11,588	$	91,719



	December 31, 2013
	Fair Value Measurements at Reporting Date Using
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Assets
Equity available-for-sale securities	$	11,633	$	11,633	$	—
Fixed-income available-for-sale securities	71,690		—		71,690
Fixed income securities owned	21,133		—		21,133
Investment funds sponsored by LSV	4,849		4,849		—
	$	109,305	$	16,482	$	92,823

Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2014

Marketable Securities [Abstract]

Investments Available For Sale

Investments available for sale classified as non-current assets consist of:



	At December 31, 2014
	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Fair Value
SEI-sponsored mutual funds	$	8,685	$	134	$	(95	)	$	8,724
Equities and other mutual funds	2,695		169		—			2,864
Debt securities	64,333		1,688		—			66,021
	$	75,713	$	1,991	$	(95	)	$	77,609



	At December 31, 2013
	Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value
SEI-sponsored mutual funds	$	7,612	$	1,242	$	—	$	8,854
Equities and other mutual funds	2,615		164		—		2,779
Debt securities	71,280		410		—		71,690
	$	81,507	$	1,816	$	—	$	83,323

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References+ Details

Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2014

Stockholders' Equity Note [Abstract]

Assumptions Used In The Weighted Average Fair Value Of The Stock Options Granted

The weighted average fair value of the Company’s stock options granted during 2014, 2013 and 2012 were $10.88, $10.45 and $6.73, respectively, using the following assumptions:



	2014		2013		2012
Expected term (in years)	6.79		6.92		6.75
Expected volatility	26.98	%	31.46	%	34.90	%
Expected dividend yield	1.15	%	1.21	%	1.46	%
Risk-free interest rate	2.04	%	2.12	%	1.03	%

Stock-based Compensation Expense

The Company recognized stock-based compensation expense in its Consolidated Financial Statements in 2014, 2013 and 2012 as follows:



	2014			2013			2012
Stock-based compensation expense	$	13,463		$	37,865		$	15,736
Less: Deferred tax benefit	(4,704		)	(13,823		)	(5,650		)
Stock-based compensation expense, net of tax	$	8,759		$	24,042		$	10,086

Stock Option Plans

This table presents certain information relating to the Company’s stock option plans for 2014, 2013 and 2012:



	Number of Shares		Weighted Avg. Price
Balance as of December 31, 2011	27,043,000		$	20.06
Granted	2,470,000		22.40
Exercised	(3,136,000	)	15.19
Expired or canceled	(767,000	)	22.61
Balance as of December 31, 2012	25,610,000		$	20.81
Granted	2,281,000		33.67
Exercised	(3,733,000	)	17.26
Expired or canceled	(521,000	)	22.25
Balance as of December 31, 2013	23,637,000		$	22.58
Granted	2,293,000		40.05
Exercised	(5,261,000	)	19.52
Expired or canceled	(208,000	)	28.83
Balance as of December 31, 2014	20,461,000		$	25.26

Exercisable as of December 31, 2014	10,295,000		$	20.58
Available for future grant as of December 31, 2014	28,626,000

Stock Options Outstanding And Exercisable

This table summarizes information relating to all options outstanding and exercisable at December 31, 2014:



				Options Outstanding at December 31, 2014				Options Exercisable at December 31, 2014
Range of Exercise Prices (Per Share)				Number of Shares	Weighted Average Exercise Price (Per Share)		Weighted Average Remaining Contractual Life (Years)	Number of Shares	Weighted Average Exercise Price (Per Share)		Weighted Average Remaining Contractual Life (Years)
$	14.62	-	15.77	4,073,000	$	15.19	5.48	2,915,000	$	14.95	5.69
17.65		-	21.05	3,534,000	18.20		3.71	3,519,000	18.27		4.49
22.45		-	23.86	4,399,000	23.20		6.93	1,960,000	21.92		4.35
27.03		-	32.49	4,073,000	30.95		2.68	1,901,000	26.57		5.09
33.73		-	40.64	4,382,000	37.10		9.50	—	31.17		4.00
				20,461,000				10,295,000

Common Stock Buyback

The following table provides the total number of shares repurchased and the related total costs in 2014, 2013 and 2012:



Year	Total Number of Shares Repurchased	Total Cost
2014	7,888,000	$	278,357
2013	6,789,000	209,942
2012	7,528,000	155,264

Accumulated Other Comprehensive Income (Loss), Net of Tax (Tables)

12 Months Ended

Dec. 31, 2014

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Schedule Of Accumulated Other Comprehensive Income (Loss), Net Of Tax

Components of Accumulated other comprehensive income (loss) attributable to SEI Investments shareholders consisted of:



	Foreign Currency Translation Adjustments			Unrealized Holding Gains (Losses) on Investments			Accumulated Other Comprehensive Income (Loss)
Balance, January 1, 2012	$	(674	)	$	2,574		$	1,900

Other comprehensive income before reclassifications	4,084			341			4,425
Amounts reclassified from accumulated other comprehensive income	—			(86		)	(86		)
Net current-period other comprehensive income	4,084			255			4,339

Balance, December 31, 2012	$	3,410		$	2,829		$	6,239

Other comprehensive loss before reclassifications	(3,309		)	(1,149		)	(4,458		)
Amounts reclassified from accumulated other comprehensive income	—			(294		)	(294		)
Net current-period other comprehensive loss	(3,309		)	(1,443		)	(4,752		)

Balance, December 31, 2013	$	101		$	1,386		$	1,487

Other comprehensive loss before reclassifications	(10,189		)	441			(9,748		)
Amounts reclassified from accumulated other comprehensive income	—			(634		)	(634		)
Net current-period other comprehensive loss	(10,189		)	(193		)	(10,382		)

Balance, December 31, 2014	$	(10,088	)	$	1,193		$	(8,895	)

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2014

Income Tax Disclosure [Abstract]

Schedule of Federal and State and Foreign Income Tax Provision

The federal and state and foreign income tax provision is summarized as follows:



Year Ended December 31,	2014		2013			2012
Current
Federal	$	155,273	$	153,856		$	112,247
State	8,744		11,542			5,284
Foreign	5,254		4,727			4,511
	169,271		170,125			122,042
Deferred, including current deferred
Federal	1,667		(2,214		)	(2,708		)
State	11		(16,264		)	(2,199		)
Foreign	—		(4,814		)	3,970
	1,678		(23,292		)	(937		)
Income taxes attributable to the noncontrolling interest	—		91			357
Total income taxes	$	170,949	$	146,924		$	121,462

Components of Net Income Before Income Taxes

The components of Income before income taxes are summarized as follows:



Year Ended December 31,	2014		2013		2012
Domestic	$	475,175	$	427,915	$	319,907
Foreign	14,487		7,042		8,046
	$	489,662	$	434,957	$	327,953

Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate

The effective income tax rate differs from the federal income tax statutory rate due to the following:



Year Ended December 31,	2014		2013		2012
Statutory rate	35.0	%	35.0	%	35.0	%
State taxes, net of Federal tax benefit	1.2		1.5		1.0
Foreign tax expense and tax rate differential	(0.7	)	0.5		1.6
Research and development tax credit	(0.4	)	(0.8	)	—
Domestic Production Activities Deduction	(0.4	)	(0.5	)	(0.6	)
PA Tax Law changes and change in valuation allowance on loss carryforwards	—		(2.4	)	(0.3	)
Net change in uncertain tax positions	0.3		0.1		0.5
Other, net	(0.1	)	0.3		(0.3	)
	34.9	%	33.7	%	36.9	%

Schedule of Deferred Tax Assets and Liabilities

The net deferred income tax liability is comprised of:



Year Ended December 31,	2014			2013
Current deferred income taxes:
Gross assets	$	2,952		$	2,458
Gross liabilities	(4,366		)	(4,111		)
	(1,414		)	(1,653		)
Valuation allowance	—			—
	(1,414		)	(1,653		)
Long-term deferred income taxes:
Gross assets	66,335			69,483
Gross liabilities	(113,581		)	(121,317		)
	(47,246		)	(51,834		)
Valuation allowance	(16,509		)	(14,738		)
	(63,755		)	(66,572		)
Net deferred income tax liability	$	(65,169	)	$	(68,225	)

Schedule of Temporary Differences Representing Net Deferred Tax Assets or Liabilities

The tax effect of significant temporary differences representing deferred tax liabilities is:



Year Ended December 31,	2014			2013
Difference in financial reporting and income tax depreciation methods	$	(3,637	)	$	(7,043	)
Reserves not currently deductible	209			235
Capitalized software currently deductible for tax purposes, net of amortization	(118,841		)	(119,800		)
State deferred income taxes	(420		)	251
Revenue and expense recognized in different periods for financial reporting and income tax purposes	6,212			3,856
Unrealized holding gain on investments	(475		)	(308		)
Stock-based compensation expense	38,989			45,555
State net operating loss carryforward	24,150			21,215
Valuation allowance on deferred tax assets	(16,509		)	(14,738		)
Federal benefit of state tax deduction for uncertain tax positions	2,913			2,643
Foreign tax credit	2,327			—
Foreign deferred including taxes on cumulative undistributed earnings of SEI AK	(87		)	(91		)
Net deferred income tax liability	$	(65,169	)	$	(68,225	)

Schedule of Unrecognized Tax Benefits Roll Forward

A reconciliation of the beginning and ending amount of unrecognized tax benefit is as follows:



	2014			2013			2012
Balance as of January 1	$	12,028		$	11,553		$	9,410
Tax positions related to current year:
Gross additions	1,957			1,834			2,196
Gross reductions	—			—			—
	1,957			1,834			2,196
Tax positions related to prior years:
Gross additions	1,369			3,435			1,990
Gross reductions	—			—			—
	1,369			3,435			1,990
Settlements	—			(3,772		)	(99		)
Lapses on statute of limitations	(1,336		)	(1,022		)	(1,944		)
Balance as of December 31	$	14,018		$	12,028		$	11,553

Business Segment Information (Tables)

12 Months Ended

Dec. 31, 2014

Segment Reporting [Abstract]

Financial Information About Business Segments

The following tables highlight certain financial information about each of the Company’s business segments for the years ended December 31, 2014, 2013 and 2012:



	Private Banks		Investment Advisors		Institutional Investors		Investment Managers		Investments In New Businesses			Total
	For the Year Ended December 31, 2014
Revenues	$	441,467	$	283,811	$	284,677	$	251,310	$	4,740		$	1,266,005
Expenses	399,620		146,500		140,659		159,176		18,377			864,332
Operating profit (loss)	$	41,847	$	137,311	$	144,018	$	92,134	$	(13,637	)	$	401,673
Gain on sale of subsidiary	5,582		—		—		—		—			5,582
Total profit (loss)	$	47,429	$	137,311	$	144,018	$	92,134	$	(13,637	)	$	407,255



	Private Banks		Investment Advisors		Institutional Investors		Investment Managers		Investments In New Businesses			Total
	For the Year Ended December 31, 2013
Revenues	$	397,138	$	241,252	$	257,658	$	226,081	$	4,003		$	1,126,132
Expenses	392,399		133,962		133,218		148,977		15,723			824,279
Operating profit (loss)	$	4,739	$	107,290	$	124,440	$	77,104	$	(11,720	)	$	301,853
Gain on sale of subsidiary	22,112		—		—		—		—			22,112
Total profit (loss)	$	26,851	$	107,290	$	124,440	$	77,104	$	(11,720	)	$	323,965



	Private Banks		Investment Advisors		Institutional Investors		Investment Managers		Investments In New Businesses			Total
	For the Year Ended December 31, 2012
Revenues	$	364,788	$	202,703	$	227,889	$	193,484	$	3,658		$	992,522
Expenses	357,001		120,146		116,546		127,525		14,954			736,172
Operating profit (loss)	$	7,787	$	82,557	$	111,343	$	65,959	$	(11,296	)	$	256,350

Reconciliation Of Total Operating Profit Reported For Business Segments To Income From Operations In Consolidated Statements Of Operations



Year Ended December 31,	2014			2013			2012
Total operating profit from segments above	$	401,673		$	301,853		$	256,350
Corporate overhead expenses	(48,889		)	(53,733		)	(45,759		)
Noncontrolling interest reflected in segments	—			289			975
Income from operations	$	352,784		$	248,409		$	211,566

Additional Information Pertaining To Business Segments

The following tables provide additional information for the years ended December 31, 2014, 2013 and 2012 pertaining to our business segments:



	Capital Expenditures (1)						Depreciation
Year Ended December 31,	2014		2013		2012		2014		2013		2012
Private Banks	$	30,883	$	34,258	$	32,509	$	13,393	$	15,506	$	15,226
Investment Advisors	13,783		12,611		11,193		2,507		2,091		1,981
Institutional Investors	4,575		2,712		2,781		1,041		893		1,012
Investment Managers	9,505		4,871		5,494		2,917		1,970		1,914
Investments in New Businesses	2,547		639		632		1,983		1,589		1,716
Total from business segments	$	61,293	$	55,091	$	52,609	$	21,841	$	22,049	$	21,849
Corporate Overhead	2,053		760		1,465		607		448		737
	$	63,346	$	55,851	$	54,074	$	22,448	$	22,497	$	22,586

(1) Capital expenditures include additions to property and equipment and capitalized software.



	Amortization
Year Ended December 31,	2014		2013		2012
Private Banks	$	24,993	$	22,379	$	22,218
Investment Advisors	9,228		8,234		7,167
Institutional Investors	1,430		1,274		1,208
Investment Managers	954		851		804
Investments in New Businesses	1,846		1,636		1,249
Total from business segments	$	38,451	$	34,374	$	32,646
Corporate Overhead	228		228		612
	$	38,679	$	34,602	$	33,258



	Total Assets
	2014		2013
Private Banks	$	417,890	$	430,613
Investment Advisors	134,371		124,028
Institutional Investors	118,397		97,816
Investment Managers	134,614		122,969
Investments in New Businesses	21,830		6,064
Total from business segments	$	827,102	$	781,490
Corporate Overhead (2)	715,773		657,679
	$	1,542,875	$	1,439,169

(2) Unallocated assets primarily consist of cash and cash equivalents, marketable securities, and certain other shared services assets.

Revenues And Assets Based On Location

The following table presents revenues based on the location of the use of the products or services:



For the Year Ended December 31,	2014		2013		2012
United States	$	1,063,223	$	962,266	$	843,407
International operations	202,782		163,866		149,115
	$	1,266,005	$	1,126,132	$	992,522

The following table presents assets based on their location:



	2014		2013
United States	$	1,315,036	$	1,231,565
International operations	227,839		207,604
	$	1,542,875	$	1,439,169

- Definition

Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.

+ References+ Details

Sale of SEI Asset Korea (Tables)

12 Months Ended

Dec. 31, 2014

Discontinued Operations and Disposal Groups [Abstract]

Schedule of Revenues and Net Income of Sold Segment

SEI AK revenues and net income included in the Company's Consolidated Statement of Operations were as follows:



	For the Period January 1, 2013 through March 28, 2013


				2012
Revenues	$	2,889		$	11,514

Net income	$	796		$	2,703
Less: Income attributable to the noncontrolling interests	(350		)	(1,186		)
Net income attributable to SEI AK	$	446		$	1,517

- Definition

Tabular disclosure of disposal groups, which may include the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the classification and carrying value of the assets and liabilities comprising the disposal group, and the segment in which the disposal group was reported. Also may include the amount of adjustments to amounts previously reported in discontinued operations such as resolution of contingencies arising from the disposal transaction or the operations of the component prior to disposal.

+ References+ Details

Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2014

Quarterly Financial Data [Abstract]

Quarterly Financial Data

Quarterly Financial Data (Unaudited)



	For the Three Months Ended
2014	March 31			June 30			September 30			December 31
Revenues	$	302,386		$	318,815		$	322,047		$	322,757
Income before income taxes	$	116,665		$	128,854		$	128,618		$	115,525
Net income attributable to SEI	$	74,820		$	82,813		$	83,983		$	77,097
Basic earnings per share	$	0.44		$	0.49		$	0.50		$	0.46
Diluted earnings per share	$	0.43		$	0.48		$	0.49		$	0.45

Effective income tax rate	35.9		%	35.7		%	34.7		%	33.3		%

Gain on sale of subsidiary (Note 15)	$	5,582		$	—		$	—		$	—
Diluted earnings per share (1)	$	0.02		$	—		$	—		$	—

Loss from impairment charge (Note 2)	$	—		$	—		$	—		$	11,266
Diluted earnings per share (2)	$	—		$	—		$	—		$	0.06

(1) Attributable to gain on sale of subsidiary.

(2) Attributable to loss from impairment charge.



	For the Three Months Ended
2013	March 31			June 30			September 30			December 31
Revenues	$	271,879		$	274,574		$	280,655		$	299,024
Income before income taxes	$	110,962		$	129,387		$	93,986		$	101,063
Net income attributable to SEI	$	71,920		$	83,494		$	67,195		$	65,515
Basic earnings per share	$	0.42		$	0.48		$	0.39		$	0.39
Diluted earnings per share	$	0.41		$	0.47		$	0.38		$	0.37

Effective income tax rate	34.9		%	35.5		%	28.5		%	35.2		%

Gain on sale of subsidiary (Note 15)	$	22,112		$	—		$	—		$	—
Diluted earnings per share (3)	$	0.08		$	—		$	—		$	—

Settlement agreement (Note 16)	$	—		$	43,429		$	—		$	—
Diluted earnings per share (4)	$	—		$	0.16		$	—		$	—

Summary of Significant Accounting Policies (Narrative) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended				3 Months Ended	12 Months Ended											3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2014 SEI Wealth Platform [Member]	Dec. 31, 2014 SEI Wealth Platform [Member]	Dec. 31, 2013 SEI Wealth Platform [Member]	Dec. 31, 2012 SEI Wealth Platform [Member]	Dec. 31, 2012 SEI Wealth Platform [Member] Amortization [Member]	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014 Sei Investments Europe Limited [Member]	Dec. 31, 2013 Sei Investments Europe Limited [Member]	Dec. 31, 2014 Sei Investments Distribution Co Sidco [Member]	Dec. 31, 2013 Sei Investments Distribution Co Sidco [Member]	Dec. 31, 2014 Maximum [Member]	Dec. 31, 2014 Weighted Average [Member] SEI Wealth Platform [Member]	Dec. 31, 2014 Building and Building Improvements [Member] Minimum [Member]	Dec. 31, 2014 Building and Building Improvements [Member] Maximum [Member]	Dec. 31, 2014 Computer Equipment [Member] Minimum [Member]	Dec. 31, 2014 Computer Equipment [Member] Maximum [Member]	Dec. 31, 2014 Furniture and Fixtures [Member] Minimum [Member]	Dec. 31, 2014 Furniture and Fixtures [Member] Maximum [Member]	Dec. 31, 2014 Equity Method Investee [Member] Minimum [Member]	Dec. 31, 2014 Equity Method Investee [Member] Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage																50.00%								20.00%	50.00%
Cash and cash equivalents	$ 667,446	$ 578,273	$ 452,247	$ 420,986						$ 435,268	$ 387,201
Restricted cash	5,801	5,500										5,000	5,000	500	500
Estimated useful life of property and equipment																		25 years	39 years	3 years	5 years	3 years	5 years
Net book value of the SEI Wealth Platform	309,040	312,615			309,040	309,040
Capitalized software development costs related to the SEI Wealth Platform						34,877	39,500	31,004
Conversion option payment included in software development costs							8,812
Estimated useful life of the SEI Wealth Platform					15 years												7 years 6 months
Amortization expense related to the SEI Wealth Platform						38,357	34,045	32,177
Capitalized computer software impairments									$ 2,661
Anti-dilutive employee stock options	10,166	7,736	13,202
Anti-dilutive employee stock options, average exercise price per share	$ 30.00	$ 30.54	$ 24.76

Summary of Significant Accounting Policies (Calculation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Basic earnings per common share, Net income attributable to SEI (Numerator)	$ 77,097	$ 83,983	$ 82,813	$ 74,820	$ 65,515	$ 67,195	$ 83,494	$ 71,920	$ 318,713	$ 288,124	$ 206,848
Shares used to compute basic earnings per share									168,246	171,561	174,295
Basic earnings per common share	$ 0.46	$ 0.50	$ 0.49	$ 0.44	$ 0.39	$ 0.39	$ 0.48	$ 0.42	$ 1.89	$ 1.68	$ 1.19
Dilutive effect of stock options, Net income attributable to SEI (Numerator)									0	0	0
Dilutive effect of stock options, shares									4,319	4,157	1,577
Diluted earnings per common share, Net income attributable to SEI (Numerator)									$ 318,713	$ 288,124	$ 206,848
Shares used to compute diluted earnings per share									172,565	175,718	175,872
Diluted earnings per common share	$ 0.45	$ 0.49	$ 0.48	$ 0.43	$ 0.37	$ 0.38	$ 0.47	$ 0.41	$ 1.85	$ 1.64	$ 1.18

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References+ Details

- Definition

This element represents the weighted average total number of shares issued throughout the period including the first (beginning balance outstanding) and last (ending balance outstanding) day of the period before considering any reductions (for instance, shares held in treasury) to arrive at the weighted average number of shares outstanding. Weighted average relates to the portion of time within a reporting period that common shares have been issued and outstanding to the total time in that period. Such concept is used in determining the weighted average number of shares outstanding for purposes of calculating earnings per share (basic).

+ References+ Details

Investment In Unconsolidated Affiliates (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended						12 Months Ended				12 Months Ended			3 Months Ended	12 Months Ended			36 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 30, 2011 LSV Employee Group II [Member]	Oct. 31, 2012 LSV Employee Group III [Member]	Apr. 30, 2011 Financial Guarantee [Member] LSV Employee Group II [Member]	Dec. 31, 2014 Financial Guarantee [Member] LSV Employee Group III [Member]	Oct. 31, 2012 Financial Guarantee [Member] LSV Employee Group III [Member]	Jan. 30, 2015 Financial Guarantee [Member] LSV Employee Group III [Member] Subsequent Event [Member]	Oct. 31, 2012 Financial Guarantee [Member] LSV Asset Management [Member]	Dec. 31, 2014 LSV Asset Management [Member]	Dec. 31, 2013 LSV Asset Management [Member]	Dec. 31, 2012 LSV Asset Management [Member]	Dec. 31, 2014 Gao Fu [Member]	Dec. 31, 2014 Gao Fu [Member]	Dec. 31, 2013 Gao Fu [Member]	Dec. 31, 2012 Gao Fu [Member]	Dec. 31, 2013 Gao Fu [Member]	Dec. 31, 2014 Maximum [Member]
Investments in and Advances to Affiliates [Line Items]
Equity method investment, ownership percentage											39.30%			27.60%	27.60%				50.00%
Total investment in equity method investee											$ 52,940
Company's share in the earnings (losses) of equity method investee	127,786	118,076	98,671								140,211	118,983	99,989		(1,159)	(907)	(1,318)
Distributions received from unconsolidated affiliate	137,866	137,104	92,227								137,866	137,104	92,227
Guarantor obligations, maximum exposure						3,655		45,000	38,658	24,930
Guarantor obligations, current carrying value									0
Purchase of partnership interest value					77,700
Purchase price of partnership interest				4,300
Guarantor obligations, term							5 years
Loans payable					69,930
Payments for ownership interest in Gao Fu	2,000	2,604	3,819												3,000			13,000
Loss from impairment charge														$ (11,266)

Investment In Unconsolidated Affiliates (Condensed Statements of Operations of LSV) (Details) (LSV Asset Management [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
LSV Asset Management [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Summarized Financial Information, Revenue	$ 422,064	$ 354,094	$ 296,261
Equity Method Investment, Summarized Financial Information, Net Income (Loss)	$ 356,824	$ 302,316	$ 250,165

- Definition

The amount of net income (loss) reported by an equity method investment of the entity.

+ References+ Details

Investment In Unconsolidated Affiliates (Condensed Balance Sheets of LSV) (Details) (LSV Asset Management [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
LSV Asset Management [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Summarized Financial Information, Current Assets	$ 133,657	$ 118,630
Equity Method Investment, Summarized Financial Information, Noncurrent Assets	2,269	2,588
Equity Method Investment, Summarized Financial Information, Assets	135,926	121,218
Equity Method Investment, Summarized Financial Information, Current Liabilities	35,208	26,103
Equity Method Investment Summarized Financial Information, Equity	100,718	95,115
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	$ 135,926	$ 121,218

- Definition

The amount of assets reported by an equity method investment of the entity.

+ References+ Details

- Definition

The amount of current assets reported by an equity method investment of the entity.

+ References+ Details

- Definition

The amount of current liabilities reported by an equity method investment of the entity.

+ References+ Details

- Definition

The amount of liabilities and equity reported by an equity method investment of the entity.

+ References+ Details

- Definition

The amount of noncurrent assets reported by an equity method investment of the entity.

+ References+ Details

Composition of Certain Financial Statement Captions (Receivables) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Items Included in Consolidated Statement of Financial Condition [Abstract]
Trade receivables	$ 48,394	$ 44,502
Fees earned, not billed	139,038	128,248
Other receivables	7,771	14,565
Gross receivables	195,203	187,315
Less: Allowance for doubtful accounts	(784)	(651)
Receivables, net	$ 194,419	$ 186,664

Composition of Certain Financial Statement Captions (Property And Equipment) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	$ 366,830	$ 339,059
Less: Accumulated depreciation	(241,295)	(220,064)
Property and Equipment, net	125,535	118,995
Depreciation expense	22,448	22,497	22,586
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	149,890	138,426
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	78,266	70,117
Land [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	9,997	9,929
Purchased software [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	104,964	96,268
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	16,944	17,060
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	5,675	4,670
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	$ 1,094	$ 2,589

Composition of Certain Financial Statement Captions (Accrued Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Items Included in Consolidated Statement of Financial Condition [Abstract]
Accrued employee compensation	$ 73,269	$ 69,256
Accrued employee benefits and other personnel	6,482	9,647
Accrued consulting, outsourcing and professional fees	18,915	19,311
Accrued sub-advisory, distribution and other asset management fees	31,913	25,018
Accrued dividend payable	40,178	37,314
Other accrued liabilities	36,672	27,577
Total accrued liabilities	$ 207,429	$ 188,123

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for professional fees, such as for legal and accounting services received. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References+ Details

- Definition

Carrying value as of the balance sheet date of the obligations incurred through that date and payable for employees' services provided. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References+ Details

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable arising from transactions not otherwise specified in the taxonomy. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References+ Details

Fair Value Measurements (Fair Value Of Certain Financial Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity available-for-sale securities	$ 11,588	$ 11,633
Fixed income available-for-sale securities	66,021	71,690
Fixed income securities owned	21,175	21,133
Investment funds sponsored by LSV	4,523	4,849
Assets, fair value	103,307	109,305
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity available-for-sale securities	11,588	11,633
Fixed income available-for-sale securities	0	0
Fixed income securities owned	0	0
Investment funds sponsored by LSV	0	4,849
Assets, fair value	11,588	16,482
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity available-for-sale securities	0	0
Fixed income available-for-sale securities	66,021	71,690
Fixed income securities owned	21,175	21,133
Investment funds sponsored by LSV	4,523	0
Assets, fair value	$ 91,719	$ 92,823

Marketable Securities (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Net unrealized holding gains	$ 1,193	$ 1,386
Unrealized holding gains during the period, income tax expense	703	430
Available-for-sale securities, gross realized gains	1,401	1,236
Available-for-sale securities, gross realized losses	448	772
Investment funds sponsored by LSV	4,523	4,849
Securities owned	21,175	21,133
Investment funds sponsored by LSV [Member]
Schedule of Investments [Line Items]
Investment funds sponsored by LSV	4,523	4,849
Change in fair value of investment funds sponsored by LSV	$ (326)	$ 143	$ 1,004

Marketable Securities (Investments Available For Sale) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Investment Available for Sale, Cost Amount	$ 75,713	$ 81,507
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	1,991	1,816
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(95)	0
Available-for-sale Securities	77,609	83,323
SEI-sponsored mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment Available for Sale, Cost Amount	8,685	7,612
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	134	1,242
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(95)	0
Available-for-sale Securities	8,724	8,854
Equities and other mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment Available for Sale, Cost Amount	2,695	2,615
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	169	164
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Available-for-sale Securities	2,864	2,779
Debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment Available for Sale, Cost Amount	64,333	71,280
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	1,688	410
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Available-for-sale Securities	$ 66,021	$ 71,690

Line Of Credit (Details) (Line of Credit [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Line of Credit Facility [Line Items]
Debt Instrument, Term	5 years
Credit facility	$ 300,000
Credit facility, expiration date	Feb. 02, 2017
Credit facility, commitment fee per annum on daily unused portion, percent	0.15%
Aggregate amount that may increase under credit facility	100,000
Credit Facility, commitment fees	$ 458	$ 458	$ 585
London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Credit facility interest accrued, percentage above LIBOR	1.25%

Shareholders' Equity (Narrative) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended				12 Months Ended			0 Months Ended		12 Months Ended
	Dec. 09, 2014	Jun. 24, 2014	May 21, 2014	Dec. 28, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 06, 2015 Subsequent Event [Member]	Dec. 31, 2014 Common Stock Buyback [Member]	Dec. 31, 2014 Minimum [Member]	Dec. 31, 2014 Maximum [Member]	Dec. 31, 2014 2014 Equity Compensation Plan [Member] Tranche One [Member]	Dec. 31, 2014 2014 Equity Compensation Plan [Member] Tranche Two [Member]	Dec. 31, 2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rate												50.00%	50.00%
Weighted average fair value of stock options granted					$ 10.88	$ 10.45	$ 6.73
Change in management estimate of stock-based compensation expense amortization						$ 19,637
Unrecognized compensation cost					45,115
Weighted average period for recognition of unrecognized compensation cost					2 years 5 months 12 days
Total options that were exercisable					10,295,000	14,601,000	9,760,000
Expiration date for options outstanding										Dec. 14, 2015	Dec. 09, 2024
Options outstanding weighted average remaining contractual life, years					5 years 9 months 15 days
Total intrinsic value of options exercised					83,196	47,392
Aggregate intrinsic value of options exercisable					200,328
Total intrinsic value of options outstanding					302,441
Share price of SEI common stock					$ 40.04
Employee stock purchase plan, employee eligible percentage on offerings of common stock														85.00%
Shares reserved under the plan														15,600,000
Issuance of common stock under the employee stock purchase plan, shares														11,732,000
Remaining stock repurchase authorization amount									102,713
Rights received by common shareholder for each common share outstanding, rights					1
Series A Junior Participating Preferred stock, par value					$ 0.05	$ 0.05
Securities and assets of equivalent value, purchase price, per unit					$ 150
Number of days, rights become exercisable following public announcement					0 years 0 months 10 days
Acquiring Person, beneficial ownership of the outstanding common stock, minimum percentage					20.00%
Common shares received by holders upon surrender of rights, percentage					50.00%
Rights non-voting, redeemable days					0 years 0 months 10 days
Right redeemable price, per right					0.01
Dividends declared per common share	$ 0.24		$ 0.22		$ 0.46	$ 0.42	$ 0.63
Dividends paid per common share		$ 0.22						$ 0.24
Dividends declared				55,149	77,158	71,665	108,817
Dividends paid				$ 55,149

Shareholders' Equity (Assumptions Used In The Weighted Average Fair Value Of Stock Options Granted) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected Term	6 years 9 months 15 days	6 years 11 months 1 day	6 years 9 months
Expected Volatility Rate	26.98%	31.46%	34.90%
Expected Dividend Rate	1.15%	1.21%	1.46%
Risk Free Interest Rate	2.04%	2.12%	1.03%

Shareholders' Equity (Stock-Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stockholders' Equity Note [Abstract]
Stock-based compensation expense	$ 13,463	$ 37,865	$ 15,736
Less: Deferred tax benefit	(4,704)	(13,823)	(5,650)
Stock-based compensation expense, net of tax	$ 8,759	$ 24,042	$ 10,086

Shareholders' Equity (Stock Option Plans) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance	23,637	25,610	27,043
Balance, weighted avg. price	$ 22.58	$ 20.81	$ 20.06
Granted	2,293	2,281	2,470
Granted, weighted avg. price	$ 40.05	$ 33.67	$ 22.40
Exercised	(5,261)	(3,733)	(3,136)
Exercised, weighted avg. price	$ 19.52	$ 17.26	$ 15.19
Expired or canceled	(208)	(521)	(767)
Expired or canceled, weighted avg. price	$ 28.83	$ 22.25	$ 22.61
Balance	20,461	23,637	25,610
Balance, weighted avg. price	$ 25.26	$ 22.58	$ 20.81
Total options that were exercisable	10,295	14,601	9,760
Exercisable shares, weighted avg. price	$ 20.58
Available for future grant as of December 31, 2014	28,626

Shareholders' Equity (Stock Options Outstanding And Exercisable) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares	20,461	23,637	25,610	27,043
Weighted Average Exercise Price (Per Share)	$ 25.26	$ 22.58	$ 20.81	$ 20.06
Weighted Average Remaining Contractual Life (Years)	5 years 9 months 15 days
Number of Shares	10,295	14,601	9,760
Weighted Average Exercise Price (Per Share)	$ 20.58
Exercise Price $14.62-15.77 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range	$ 14.62
Upper range	$ 15.77
Number of Shares	4,073
Weighted Average Exercise Price (Per Share)	$ 15.19
Weighted Average Remaining Contractual Life (Years)	5 years 5 months 23 days
Number of Shares	2,915
Weighted Average Exercise Price (Per Share)	$ 14.95
Weighted Average Remaining Contractual Life (Years)	5 years 8 months 9 days
Exercise Price $17.65-21.05 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range	$ 17.65
Upper range	$ 21.05
Number of Shares	3,534
Weighted Average Exercise Price (Per Share)	$ 18.20
Weighted Average Remaining Contractual Life (Years)	3 years 8 months 16 days
Number of Shares	3,519
Weighted Average Exercise Price (Per Share)	$ 18.27
Weighted Average Remaining Contractual Life (Years)	4 years 5 months 27 days
Exercise Price $22.45-23.86 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range	$ 22.45
Upper range	$ 23.86
Number of Shares	4,399
Weighted Average Exercise Price (Per Share)	$ 23.20
Weighted Average Remaining Contractual Life (Years)	6 years 11 months 5 days
Number of Shares	1,960
Weighted Average Exercise Price (Per Share)	$ 21.92
Weighted Average Remaining Contractual Life (Years)	4 years 4 months 6 days
Exercise Price $27.03-32.49 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range	$ 27.03
Upper range	$ 32.49
Number of Shares	4,073
Weighted Average Exercise Price (Per Share)	$ 30.95
Weighted Average Remaining Contractual Life (Years)	2 years 8 months 5 days
Number of Shares	1,901
Weighted Average Exercise Price (Per Share)	$ 26.57
Weighted Average Remaining Contractual Life (Years)	5 years 1 month 2 days
Exercise Price $33.73-40.64 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range	$ 33.73
Upper range	$ 40.64
Number of Shares	4,382
Weighted Average Exercise Price (Per Share)	$ 37.10
Weighted Average Remaining Contractual Life (Years)	9 years 6 months
Number of Shares	0
Weighted Average Exercise Price (Per Share)	$ 31.17
Weighted Average Remaining Contractual Life (Years)	4 years

Shareholders' Equity (Common Stock Buyback) (Details) (Common Stock Buyback [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Common Stock Buyback [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchased and Retired During Period, Shares	7,888	6,789	7,528
Stock Repurchased During Period, Value	$ 278,357	$ 209,942	$ 155,264

Accumulated Other Comprehensive Income (Loss), Net of Tax (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 1,487	$ 6,239	$ 1,900
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive income (loss) before reclassifications	(9,748)	(4,458)	4,425
Amounts reclassified from accumulated other comprehensive income	(634)	(294)	(86)
Total other comprehensive (loss) gain, net of taxes	(10,382)	(4,752)	4,339
Ending Balance	(8,895)	1,487	6,239
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	101	3,410	(674)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive income (loss) before reclassifications	(10,189)	(3,309)	4,084
Amounts reclassified from accumulated other comprehensive income	0	0	0
Total other comprehensive (loss) gain, net of taxes	(10,189)	(3,309)	4,084
Ending Balance	(10,088)	101	3,410
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	1,386	2,829	2,574
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive income (loss) before reclassifications	441	(1,149)	341
Amounts reclassified from accumulated other comprehensive income	(634)	(294)	(86)
Total other comprehensive (loss) gain, net of taxes	(193)	(1,443)	255
Ending Balance	$ 1,193	$ 1,386	$ 2,829

- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References+ Details

Commitments and Contingencies (Schedule Of Noncancellable Minimum Commitments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
2015	$ 3,779
2016	3,023
2017	3,741
2018	6,704
2019 and thereafter	43,601
Operating leases, future minimum payments due	$ 60,848

Income Taxes (Schedule Of Federal And State And Foreign Income Tax Provision) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal, current	$ 155,273	$ 153,856	$ 112,247
State, current	8,744	11,542	5,284
Foreign, current	5,254	4,727	4,511
Current federal, state and foreign income tax	169,271	170,125	122,042
Federal, deferred	1,667	(2,214)	(2,708)
State, deferred	11	(16,264)	(2,199)
Foreign, deferred	0	(4,814)	3,970
Deferred income tax expense (benefit)	1,678	(23,292)	(937)
Income taxes attributable to the Noncontrolling interest	0	91	357
Total income taxes	$ 170,949	$ 146,924	$ 121,462

Income Taxes (Components Of Net Income Before Income Taxes) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Domestic	$ 475,175	$ 427,915	$ 319,907
Foreign	14,487	7,042	8,046
Income Loss From Continuing Operations Before Income Taxes And Minority Interest	$ 489,662	$ 434,957	$ 327,953

Income Taxes (Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate) (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory rate									35.00%	35.00%	35.00%
State taxes, net of Federal tax benefit									1.20%	1.50%	1.00%
Foreign tax expense and tax rate differential									(0.70%)	0.50%	1.60%
Research and development tax credit									(0.40%)	(0.80%)	0.00%
Domestic Production Activities Deduction									(0.40%)	(0.50%)	(0.60%)
Valuation allowance on capital losses and PA loss carryforwards									0.00%	(2.40%)	(0.30%)
Net change in uncertain tax positions									0.30%	0.10%	0.50%
Other, net									(0.10%)	0.30%	(0.30%)
Effective tax rates	33.30%	34.70%	35.70%	35.90%	35.20%	28.50%	35.50%	34.90%	34.90%	33.70%	36.90%

Income Taxes (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Undistributed earnings of foreign subsidiaries	$ 61,833
Unrecognized tax benefit, excluding interest and penalties	14,018	12,028	11,553	9,410
Unrecognized tax benefits that would affect effective tax rate	12,162
Amount included in Other long-term liabilities	10,327	8,607
Amount of previously unrecognized tax benefits recognized	1,336
Tax related interest and penalties	1,066	754	770
Current liabilities [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Amount netted against current payable account	4,757
Other long-term liabilities [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Amount included in Other long-term liabilities	10,327
Settlement and Lapse of Statute [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized tax benefits within the next 12 months	$ 1,700

- Definition

Amount of undistributed earnings of foreign subsidiaries intended to be permanently reinvested outside the country of domicile.

+ References+ Details

Income Taxes (Schedule Of Deferred Tax Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Tax Liabilities, Net, Classification [Abstract]
Gross assets	$ 2,952	$ 2,458
Gross liabilities	(4,366)	(4,111)
Current deferred income tax assets and liabilities	(1,414)	(1,653)
Valuation allowance	0	0
Current deferred income taxes	(1,414)	(1,653)
Gross assets	66,335	69,483
Gross liabilities	(113,581)	(121,317)
Long term deferred income tax assets and liabilities	(47,246)	(51,834)
Valuation allowance	(16,509)	(14,738)
Long term deferred income taxes	(63,755)	(66,572)
Net deferred income tax liability	$ (65,169)	$ (68,225)

Income Taxes (Tax Effect Of Significant Temporary Differences Representing Deferred Tax Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Tax Liabilities, Net [Abstract]
Difference in financial reporting and income tax depreciation methods	$ (3,637)	$ (7,043)
Reserves not currently deductible	209	235
Capitalized software currently deductible for tax purposes, net of amortization	(118,841)	(119,800)
State deferred income taxes	(420)	251
Revenue and expense recognized in different periods for financial reporting and income tax purpose	6,212	3,856
Unrealized holding gain on investments	(475)	(308)
Stock-based compensation expense	(38,989)	(45,555)
State net operating loss carryforward	24,150	21,215
Valuation allowance on deferred tax assets	(16,509)	(14,738)
Federal benefit of state tax deduction for uncertain tax positions	2,913	2,643
Foreign tax credit	2,327	0
Foreign deferred including taxes on cumulative undistributed earnings of SEI AK	(87)	(91)
Net deferred income tax liability	$ (65,169)	$ (68,225)

Income Taxes (Unrecognized Tax Benefit) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, Beginning Balance	$ 12,028	$ 11,553	$ 9,410
Gross additions, current year	1,957	1,834	2,196
Gross reductions, current year	0	0	0
Tax positions related to current year	1,957	1,834	2,196
Gross additions, prior year	1,369	3,435	1,990
Gross reductions, prior year	0	0	0
Tax positions related to prior years tax positions	1,369	3,435	1,990
Settlements	0	(3,772)	(99)
Lapses on statute of limitations	(1,336)	(1,022)	(1,944)
Unrecognized tax benefits, Ending Balance	$ 14,018	$ 12,028	$ 11,553

Business Segment Information (Schedule Of Financial Information About Business Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 322,757	$ 322,047	$ 318,815	$ 302,386	$ 299,024	$ 280,655	$ 274,574	$ 271,879	$ 1,266,005	$ 1,126,132	$ 992,522
Expenses									864,332	824,279	736,172
Operating profit (loss)									401,673	301,853	256,350
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									5,582	22,112
Total Profit (Loss)									407,255	323,965
Private Banks [Member]
Segment Reporting Information [Line Items]
Revenues									441,467	397,138	364,788
Expenses									399,620	392,399	357,001
Operating profit (loss)									41,847	4,739	7,787
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									5,582	22,112
Total Profit (Loss)									47,429	26,851
Investment Advisors [Member]
Segment Reporting Information [Line Items]
Revenues									283,811	241,252	202,703
Expenses									146,500	133,962	120,146
Operating profit (loss)									137,311	107,290	82,557
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									0	0
Total Profit (Loss)									137,311	107,290
Institutional Investors [Member]
Segment Reporting Information [Line Items]
Revenues									284,677	257,658	227,889
Expenses									140,659	133,218	116,546
Operating profit (loss)									144,018	124,440	111,343
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									0	0
Total Profit (Loss)									144,018	124,440
Investment Managers [Member]
Segment Reporting Information [Line Items]
Revenues									251,310	226,081	193,484
Expenses									159,176	148,977	127,525
Operating profit (loss)									92,134	77,104	65,959
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									0	0
Total Profit (Loss)									92,134	77,104
Investments In New Businesses [Member]
Segment Reporting Information [Line Items]
Revenues									4,740	4,003	3,658
Expenses									18,377	15,723	14,954
Operating profit (loss)									(13,637)	(11,720)	(11,296)
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									0	0
Total Profit (Loss)									$ (13,637)	$ (11,720)

Business Segment Information (Reconciliation Of Total Operating Profit Reported For Business Segments To Income From Operations In Consolidated Statements Of Operations) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total operating profit from segments above	$ 401,673	$ 301,853	$ 256,350
Noncontrolling interest reflected in segments	0	350	1,186
Income from operations	352,784	248,409	211,566
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total operating profit from segments above	401,673	301,853	256,350
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Corporate overhead expenses	(48,889)	(53,733)	(45,759)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Noncontrolling interest reflected in segments	$ 0	$ 289	$ 975

Business Segment Information (Schedule Of Additional Information Pertaining To Business Segments) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Capital Expenditures	$ 63,346	$ 55,851	$ 54,074
Depreciation	22,448	22,497	22,586
Amortization	38,679	34,602	33,258
Assets	1,542,875	1,439,169
Private Banks [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	30,883	34,258	32,509
Depreciation	13,393	15,506	15,226
Amortization	24,993	22,379	22,218
Assets	417,890	430,613
Investment Advisors [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	13,783	12,611	11,193
Depreciation	2,507	2,091	1,981
Amortization	9,228	8,234	7,167
Assets	134,371	124,028
Institutional Investors [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	4,575	2,712	2,781
Depreciation	1,041	893	1,012
Amortization	1,430	1,274	1,208
Assets	118,397	97,816
Investment Managers [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	9,505	4,871	5,494
Depreciation	2,917	1,970	1,914
Amortization	954	851	804
Assets	134,614	122,969
Investments In New Businesses [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	2,547	639	632
Depreciation	1,983	1,589	1,716
Amortization	1,846	1,636	1,249
Assets	21,830	6,064
Total From Business Segments [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	61,293	55,091	52,609
Depreciation	21,841	22,049	21,849
Amortization	38,451	34,374	32,646
Assets	827,102	781,490
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	2,053	760	1,465
Depreciation	607	448	737
Amortization	228	228	612
Assets	$ 715,773	$ 657,679

Business Segment Information (Schedule of Revenues And Assets Based On Location) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues	$ 322,757	$ 322,047	$ 318,815	$ 302,386	$ 299,024	$ 280,655	$ 274,574	$ 271,879	$ 1,266,005	$ 1,126,132	$ 992,522
Assets	1,542,875				1,439,169				1,542,875	1,439,169
United States [Member]
Revenues									1,063,223	962,266	843,407
Assets	1,315,036				1,231,565				1,315,036	1,231,565
International Operations [Member]
Revenues									202,782	163,866	149,115
Assets	$ 227,839				$ 207,604				$ 227,839	$ 207,604

Related Party Transactions (Details) (RICs [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
RICs [Member]
Related Party Transaction [Line Items]
Investment Advisory and Administration Fees	$ 489,066	$ 422,825	$ 380,645
Distribution and Servicing Fees	66,424	47,988	37,827
Brokerage commissions revenue	$ 1,733	$ 620	$ 1,213

Sale of SEI Asset Korea (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 28, 2013 SEI Asset Korea Co., Ltd. [Member]	Dec. 31, 2014 SEI Asset Korea Co., Ltd. [Member]	Dec. 31, 2013 SEI Asset Korea Co., Ltd. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Closing date, sale of subsidiary					Mar. 28, 2013
Gain on sale of subsidiary	$ 5,582	$ 22,112	$ 0
Gain on sale of subsidiary, diluted earnings per share impact, net	$ 0.02	$ 0.08
Contingent purchase price from sale of SEI AK				11,220
Revenues and Net Income Included on Company's Consolidated Statement of Operations
Revenues				2,889		11,514
Net income				796		2,703
Less: Income attributable to the noncontrolling interests				(350)		(1,186)
Net income attributable to SEI AK				$ 446		$ 1,517

Quarterly Financial Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues	$ 322,757	$ 322,047	$ 318,815	$ 302,386	$ 299,024	$ 280,655	$ 274,574	$ 271,879	$ 1,266,005	$ 1,126,132	$ 992,522
Income before income taxes	115,525	128,618	128,854	116,665	101,063	93,986	129,387	110,962	489,662	435,398	329,496
Net income attributable to SEI Investments Company	77,097	83,983	82,813	74,820	65,515	67,195	83,494	71,920	318,713	288,124	206,848
Basic earnings per common share	$ 0.46	$ 0.50	$ 0.49	$ 0.44	$ 0.39	$ 0.39	$ 0.48	$ 0.42	$ 1.89	$ 1.68	$ 1.19
Diluted earnings per common share	$ 0.45	$ 0.49	$ 0.48	$ 0.43	$ 0.37	$ 0.38	$ 0.47	$ 0.41	$ 1.85	$ 1.64	$ 1.18
Effective income tax rate	33.30%	34.70%	35.70%	35.90%	35.20%	28.50%	35.50%	34.90%	34.90%	33.70%	36.90%
Gain on sale of subsidiary									5,582	22,112	0
Income (Loss) from extraordinary items, net of tax, per diluted share									$ 0.02	$ 0.08
Gain on sale of subsidiary [Member]
Gain on sale of subsidiary	0	0	0	5,582	0	0	0	22,112
Income (Loss) from extraordinary items, net of tax, per diluted share	$ 0.00	$ 0.00	$ 0.00	$ 0.02	$ 0.00	$ 0.00	$ 0.00	$ 0.08
Equity in earnings of unconsolidated affiliates [Member]
Loss from impairment charge	11,266	0	0	0
Income (Loss) from extraordinary items, net of tax, per diluted share	$ 0.06	$ 0.00	$ 0.00	$ 0.00
Other income [Member]
Settlement agreement					$ 0	$ 0	$ 43,429	$ 0
Income (Loss) from extraordinary items, net of tax, per diluted share					$ 0.00	$ 0.00	$ 0.16	$ 0.00

Schedule II - Valuation And Qualifying Accounts And Reserves (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance For Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 651	$ 805	$ 924
Additions, Charged to Costs and Expenses	133	0	0
Additions, Charged to Other Accounts	0	0	0
(Deductions)	0	(154)	(119)
Balance at End of Year	784	651	805
Deferred Income Tax Valuation Allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	14,738	6,879	8,585
Additions, Charged to Costs and Expenses	0	(485)	(1,706)
Additions, Charged to Other Accounts	1,771	8,344	0
(Deductions)	0	0	0
Balance at End of Year	$ 16,509	$ 14,738	$ 6,879

Variable Interest Entities - Investment Products (Details)	12 Months Ended
	Dec. 31, 2014
Variable Interest Entities Disclosure [Abstract]
Percentage not approached by expected return on any VIE investment	50.00%