SEI Investments (SEIC) 10-Q 23 Apr 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 22, 2014
Document Information [Line Items]	'	'
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-Q	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'SEIC	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	169,159,403

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current Assets:	'	'
Cash and cash equivalents	$545,552	$578,273
Restricted cash	5,500	5,500
Receivables from regulated investment companies	43,272	39,364
Receivables, net of allowance for doubtful accounts of $626 and $651	207,724	186,664
Securities owned	21,153	21,133
Other current assets	19,432	16,166
Total Current Assets	842,633	847,100
Property and Equipment, net of accumulated depreciation of $225,597 and $220,064	121,039	118,995
Capitalized Software, net of accumulated amortization of $189,219 and $180,062	312,866	312,615
Investments Available for Sale	81,660	83,323
Trading Securities	4,914	4,849
Investment in Unconsolidated Affiliates	61,756	61,370
Other Assets, net	14,113	10,917
Total Assets	1,438,981	1,439,169
Current Liabilities:	'	'
Accounts payable	8,373	16,235
Accrued liabilities	141,664	188,123
Deferred income taxes, net	1,604	1,653
Deferred revenue	2,078	1,977
Total Current Liabilities	153,719	207,988
Deferred Income Taxes	71,578	66,572
Other Long-term Liabilities	9,312	8,607
Total Liabilities	234,609	283,167
Commitments and Contingencies	'	'
SEI Investments shareholders' equity:	'	'
Common stock, $.01 par value, 750,000 shares authorized; 169,071 and 169,242 shares issued and outstanding	1,691	1,692
Capital in excess of par value	758,645	721,219
Retained earnings	444,022	431,604
Accumulated other comprehensive income, net	14	1,487
Total Shareholders' Equity	1,204,372	1,156,002
Total Liabilities and Shareholders' Equity	$1,438,981	$1,439,169

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Current Assets:	'	'
Receivables, allowance for doubtful accounts	$626	$651
Property and Equipment, accumulated depreciation	225,597	220,064
Capitalized Software, accumulated amortization	$189,219	$180,062
SEI Investments shareholders' equity:	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	169,071,000	169,242,000
Common stock, shares outstanding	169,071,000	169,242,000

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenues:	'	'
Asset management, administration and distribution fees	$225,071	$198,633
Information processing and software servicing fees	69,178	64,532
Transaction-based and trade execution fees	8,137	8,714
Total revenues	302,386	271,879
Expenses:	'	'
Subadvisory, distribution and other asset management costs	34,012	27,934
Software royalties and other information processing costs	8,553	7,487
Brokerage commissions	5,979	6,512
Compensation, benefits and other personnel	94,424	88,610
Stock-based compensation	2,823	5,293
Consulting, outsourcing and professional fees	34,933	31,849
Data processing and computer related	12,620	12,058
Facilities, supplies and other costs	15,852	18,148
Amortization	9,214	8,242
Depreciation	5,584	5,704
Total expenses	223,994	211,837
Income from operations	78,392	60,042
Net gain from investments	136	280
Interest and dividend income	777	1,053
Interest expense	-113	-113
Equity in earnings of unconsolidated affiliates	31,891	27,588
Gain on sale of subsidiary	5,582	22,112
Income before income taxes	116,665	110,962
Income taxes	41,845	38,692
Net income	74,820	72,270
Less: Net income attributable to the noncontrolling interest	0	-350
Net income attributable to SEI Investments Company	$74,820	$71,920
Basic earnings per common share	$0.44	$0.42
Shares used to compute basic earnings per share	169,306	172,598
Diluted earnings per common share	$0.43	$0.41
Shares used to compute diluted earnings per share	173,828	176,005

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]	'	'
Net income	$74,820	$72,270
Other comprehensive loss, net of tax:	'	'
Foreign currency translation adjustments	-1,966	-5,307
Unrealized gain (loss) on investments:	'	'
Unrealized gains during the period, net of income taxes of $(295) and $41	538	121
Less: reclassification adjustment for gains realized in net income, net of income taxes of $25 and $119	-45	-221
Net unrealized gain (loss) on investments	493	-100
Total other comprehensive loss, net of tax	-1,473	-5,407
Comprehensive income	73,347	66,863
Comprehensive loss attributable to the noncontrolling interest	0	101
Comprehensive income attributable to SEI Investments Company	$73,347	$66,964

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]	'	'
Unrealized gains (losses) during the period, income tax expense (benefit)	($295)	$41
Reclassification adjustment for losses (gains) realized in net income, income tax benefit (expense)	$25	$119

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:	'	'
Net income	$74,820	$72,270
Adjustments to reconcile net income to net cash provided by operating activities (See Note 1)	-30,878	-32,795
Net cash provided by operating activities	43,942	39,475
Cash flows from investing activities:	'	'
Additions to property and equipment	-7,627	-1,744
Additions to capitalized software	-9,408	-6,048
Purchases of marketable securities	-6,645	-11,578
Prepayments and maturities of marketable securities	9,077	9,835
Sales of marketable securities	0	4,211
Sale of subsidiary, net of cash transferred	0	-26,694
Other	0	20
Net cash used in investing activities	-14,603	-31,998
Cash flows from financing activities:	'	'
Purchase and retirement of common stock	-65,948	-34,466
Proceeds from issuance of common stock	35,793	24,278
Tax benefit on stock options exercised	5,409	2,563
Payment of dividends	-37,314	0
Net cash used in financing activities	-62,060	-7,625
Net decrease in cash and cash equivalents	-32,721	-148
Cash and cash equivalents, beginning of period	578,273	452,247
Cash and cash equivalents, end of period	$545,552	$452,099

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	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 various other 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 which are recognized in Transaction-based and trade execution fees.
	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.
	Basis of Presentation
	The accompanying Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States of America. Certain financial information and accompanying note disclosure normally included in the Company’s Annual Report on Form 10-K has been condensed or omitted. The interim financial information is unaudited but reflects all adjustments (consisting of only normal recurring adjustments) which are, in the opinion of management, necessary for a fair statement of financial position of the Company as of March 31, 2014, the results of operations for the three months ended March 31, 2014 and 2013, and cash flows for the three month periods ended March 31, 2014 and 2013. These interim Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements and the Notes to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
	There have been no significant changes in significant accounting policies during the three months ended March 31, 2014 as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
	Cash and Cash Equivalents
	Cash and cash equivalents includes $368,882 and $387,201 at March 31, 2014 and December 31, 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 March 31, 2014 and December 31, 2013 segregated for regulatory purposes related to trade-execution services conducted by SEI Investments (Europe) Limited. Restricted cash also includes $500 at March 31, 2014 and December 31, 2013, respectively, segregated in special reserve accounts for the benefit of customers of the Company’s broker-dealer subsidiary, SEI Investments Distribution Co. (SIDCO), in accordance with certain rules established by the Securities and Exchange Commission for broker-dealers.
	Capitalized Software
	The Company capitalized $9,408 and $6,048 of software development costs during the three months ended March 31, 2014 and 2013, respectively. As of March 31, 2014, capitalized software placed into service included on the accompanying Consolidated Balance Sheet had a weighted average remaining life of approximately 8.3 years. Amortization expense related to capitalized software was $9,157 and $8,186 during the three months ended March 31, 2014 and 2013, respectively.
	Software development costs capitalized during the three months ended March 31, 2014 and 2013 relate to the continued development of the SEI Wealth PlatformSM (the Platform). As of March 31, 2014, the net book value of the Platform was $312,819, net of accumulated amortization of $159,034. Capitalized software development costs in-progress at March 31, 2014 associated with future releases to the Platform were $12,204. The Platform has an estimated useful life of 15 years and a weighted average remaining life of 8.3 years. Amortization expense for the Platform was $9,110 and $8,068 during the three months ended March 31, 2014 and 2013, respectively.
	Reclassifications
	Certain prior year amounts have been reclassified to conform to current year presentation.
	Earnings per Share
	The calculations of basic and diluted earnings per share for the three months ended March 31, 2014 and 2013 are:
		For the Three Months Ended March 31, 2014
		Income			Shares			Per Share
		(Numerator)			(Denominator)			Amount
	Basic earnings per common share	$	74,820		169,306,000			$	0.44
	Dilutive effect of stock options	—			4,522,000
	Diluted earnings per common share	$	74,820		173,828,000			$	0.43
		For the Three Months Ended March 31, 2013
		Income			Shares			Per Share
		(Numerator)			(Denominator)			Amount
	Basic earnings per common share	$	71,920		172,598,000			$	0.42
	Dilutive effect of stock options	—			3,407,000
	Diluted earnings per common share	$	71,920		176,005,000			$	0.41
	Employee stock options to purchase 4,389,000 and 6,863,000 shares of common stock, with an average exercise price of $32.40 and $28.05, were outstanding during the three months ended March 31, 2014 and 2013, respectively, but not included in the computation of diluted earnings per common share because the effect on diluted earnings per common share would have been anti-dilutive.
	Statements of Cash Flows
	For purposes of the Consolidated Statements of Cash Flows, the Company considers investment instruments purchased with an original maturity of three months or less to be cash equivalents.
	The following table provides the details of the adjustments to reconcile net income to net cash provided by operating activities for the three months ended March 31:
		2014			2013
	Net income	$	74,820		$	72,270
	Adjustments to reconcile net income to net cash provided by operating activities:
	Depreciation	5,584			5,704
	Amortization	9,214			8,242
	Equity in earnings of unconsolidated affiliates	(31,891		)	(27,588		)
	Distributions received from unconsolidated affiliate	31,505			27,821
	Stock-based compensation	2,823			5,293
	Provision for losses on receivables	(25		)	216
	Deferred income tax expense	4,686			(7,730		)
	Gain from sale of SEI AK	(5,582		)	(22,112		)
	Net gain from investments	(136		)	(280		)
	Change in other long-term liabilities	705			368
	Change in other assets	(3,273		)	2,832
	Other	(1,901		)	(7,996		)
	Change in current asset and liabilities
	Decrease (increase) in
	Restricted cash for broker-dealer operations	—			500
	Receivables from regulated investment companies	(3,908		)	(5,473		)
	Receivables	(15,453		)	(9,127		)
	Other current assets	(3,266		)	(2,466		)
	Increase (decrease) in
	Accounts payable	(7,862		)	(4,618		)
	Accrued liabilities	(12,199		)	4,571
	Deferred revenue	101			(952		)
	Total adjustments	(30,878		)	(32,795		)
	Net cash provided by operating activities	$	43,942		$	39,475

Investment_In_Unconsolidated_A

Investment In Unconsolidated Affiliates	3 Months Ended
	Mar. 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 LSV Asset Management (LSV), a Delaware general partnership. LSV is a registered investment advisor that provides investment advisory services to institutions, including pension plans and investment companies. LSV is currently an investment sub-advisor for a small number of SEI-sponsored mutual funds. The Company accounts for its interest in LSV using the equity method because of its less than 50 percent ownership. The Company’s total partnership interest in LSV was approximately 39.3 percent and 39.8 percent during the three months ended March 31, 2014 and 2013, respectively. 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 March 31, 2014, the Company’s total investment in LSV was $51,306. The investment in LSV exceeded the underlying equity in the net assets of LSV by $3,062 which is considered goodwill embedded in the investment. The Company receives partnership distributions from LSV on a quarterly basis. The Company received partnership distributions from LSV for $31,505 and $27,821 in the three months ended March 31, 2014 and 2013, respectively.
	The Company’s proportionate share in the earnings of LSV was $32,216 and $27,806 during the three months ended March 31, 2014 and 2013, respectively.
	The following table contains the condensed statements of operations of LSV for the three months ended March 31, 2014 and 2013:
		Three Months Ended March 31,
		2014		2013
	Revenues	$	95,773	$	80,916
	Net income	81,923		70,180
	Guaranty Agreement with LSV Employee Group II
	In April 2011, LSV Employee Group II 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. (Bank of America). The Company provided an unsecured guaranty to the lenders of all the obligations of LSV Employee Group II. The lenders have the right to seek payment from the Company in the event of a default by LSV Employee Group II.
	As of April 22, 2014, the remaining unpaid principal balance of the term loan was $365. LSV Employee Group II has met all financial obligations to date regarding the scheduled repayment of the term loan since its origination. The Company, in its capacity as guarantor, currently has no obligation of payment relating to the term loan of LSV Employee Group II and, furthermore, fully expects that LSV Employee Group II will meet all of their future obligations regarding the term loan.
	Guaranty Agreement with LSV Employee Group III
	In October 2012, LSV Employee Group III purchased a portion of the partnership interest of three existing LSV employees for $77,700, of which $69,930 was financed through two syndicated term loan facilities contained in a credit agreement with The PrivateBank and Trust Company. The Company provided an unsecured guaranty for $45,000 of the obligations of LSV Employee Group III to the lenders through a guaranty agreement. The lenders have the right to seek payment from the Company in the event of a default by LSV Employee Group III. LSV agreed to provide an unsecured guaranty for $24,930 of the obligations of LSV Employee Group III to the lenders through a separate guaranty agreement.
	As of April 22, 2014, the remaining unpaid principal balances of the term loans guaranteed by LSV and the Company were $6,374 and $45,000, respectively. LSV Employee Group III has met all financial obligations to date regarding the scheduled repayment of the term loans since origination. 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 Limited (Gao Fu), a wealth services firm based in Shanghai in the Republic of China. The Company accounts for its interest in Gao Fu using the equity method. At March 31, 2014, the Company's total investment in Gao Fu was $10,450. The Company's proportionate share in the losses of Gao Fu was $325 and $218 during the three months ended March 31, 2014 and 2013, respectively.

Variable_Interest_Entities_Inv

Variable Interest Entities - Investment Products	3 Months Ended
	Mar. 31, 2014
Variable Interest Entities - Investment Products [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 and net capital gains 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. Some of the Company’s investment products have been determined to be VIEs at inception.
	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 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, is not 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 not significant. 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 not significant to the total assets of the Company.

Composition_of_Certain_Financi

Composition of Certain Financial Statement Captions	3 Months Ended
	Mar. 31, 2014
Items Included in Consolidated Statement of Financial Condition [Abstract]	'
Composition of Certain Financial Statement Captions	'
	Composition of Certain Financial Statement Captions
	Receivables
	Receivables on the accompanying Consolidated Balance Sheets consist of:
		March 31, 2014			December 31, 2013
	Trade receivables	$	56,596		$	44,502
	Fees earned, not billed	136,956			128,248
	Other receivables	14,798			14,565
		208,350			187,315
	Less: Allowance for doubtful accounts	(626		)	(651		)
		$	207,724		$	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. In addition, certain fees earned from investment operations services are calculated based on assets under administration that have a prolonged valuation process which delays billings to clients.
	Receivables from regulated investment companies on the accompanying Consolidated Balance Sheets primarily represent fees receivable for distribution, investment advisory, and administration services to various regulated investment companies sponsored by SEI.
	Property and Equipment
	Property and Equipment on the accompanying Consolidated Balance Sheets consists of:
		March 31, 2014			December 31, 2013
	Buildings	$	138,437		$	138,426
	Equipment	71,838			70,117
	Land	9,997			9,929
	Purchased software	98,472			96,268
	Furniture and fixtures	17,081			17,060
	Leasehold improvements	5,173			4,670
	Construction in progress	5,638			2,589
		346,636			339,059
	Less: Accumulated depreciation	(225,597		)	(220,064		)
	Property and Equipment, net	$	121,039		$	118,995
	The Company recognized $5,584 and $5,704 in depreciation expense related to property and equipment for the three months ended March 31, 2014 and 2013, respectively.
	Accrued Liabilities
	Accrued liabilities on the accompanying Consolidated Balance Sheets consist of:
		March 31, 2014			December 31, 2013
	Accrued employee compensation	$	29,353		$	69,256
	Accrued employee benefits and other personnel	5,683			9,647
	Accrued consulting, outsourcing and professional fees	23,475			19,311
	Accrued sub-advisory, distribution and other asset management fees	25,050			25,018
	Accrued income taxes	26,922			—
	Accrued dividend payable	—			37,314
	Other accrued liabilities	31,181			27,577
	Total accrued liabilities	$	141,664		$	188,123

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	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 equity and fixed-income mutual funds that are quoted daily. Level 2 financial assets consist of Government National Mortgage Association (GNMA) mortgage-backed pass-through certificates, Federal Home Loan Bank (FHLB) and other U.S. government agency short-term notes and investment grade commercial paper. The Company's Level 2 financial assets, with the exception of the GNMA securities, were purchased as part of a cash management program requiring only short term, top-tier investment grade government and corporate securities. The GNMA mortgage-backed pass-through certificates were purchased for the sole purpose of satisfying specific regulatory requirements imposed on our wholly-owned limited purpose federal thrift subsidiary, SEI Private Trust Company (SPTC). As a result, the Company's Level 2 financial assets are limited to only these types of fixed income securities. The valuation of the Company's Level 2 financial assets are based upon securities pricing policies and procedures utilized by third-party pricing vendors. The pricing policies and procedures applied during the three months ended March 31, 2014 were consistent with those as described in our Annual Report on Form 10-K at December 31, 2013. The Company had no Level 3 financial assets or liabilities at March 31, 2014 or December 31, 2013. There were no transfers of financial assets between levels within the fair value hierarchy during the three months ended March 31, 2014.
	The fair value of certain financial assets and liabilities of the Company was determined using the following inputs:
		At March 31, 2014
		Fair Value Measurements at Reporting Date Using
	Assets	Total		Quoted Prices		Significant
				in		Other
				Active  Markets		Observable
				for Identical		Inputs
				Assets		(Level 2)
				(Level 1)
	Equity available-for-sale securities	$	11,713	$	11,713	$	—
	Fixed income available-for-sale securities	69,947		—		69,947
	Fixed income securities owned	21,153		—		21,153
	Trading securities	4,914		4,914		—
		$	107,727	$	16,627	$	91,100
		At December 31, 2013
		Fair Value Measurements at Reporting Date Using
	Assets	Total		Quoted Prices		Significant
				in		Other
				Active  Markets		Observable
				for Identical		Inputs
				Assets		(Level 2)
				(Level 1)
	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
	Trading securities	4,849		4,849		—
		$	109,305	$	16,482	$	92,823

Marketable_Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2014
Marketable Securities [Abstract]	'
Marketable Securities	'
	Marketable Securities
	Investments Available for Sale
	Investments available for sale classified as non-current assets consist of:
		At March 31, 2014
		Cost		Gross		Gross		Fair
		Amount		Unrealized		Unrealized		Value
				Gains		Losses
	SEI-sponsored mutual funds	$	7,559	$	1,363	$	—	$	8,922
	Equities and other mutual funds	2,719		72		—		2,791
	Debt securities	68,803		1,144		—		69,947
		$	79,081	$	2,579	$	—	$	81,660
		At December 31, 2013
		Cost		Gross		Gross		Fair
		Amount		Unrealized		Unrealized		Value
				Gains		Losses
	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 gains at March 31, 2014 and December 31, 2013 were $1,879 (net of income tax expense of $700) 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 income on the accompanying Consolidated Balance Sheets.
	There were gross realized gains of $119 and gross realized losses of $49 from available-for-sale securities during the three months ended March 31, 2014. There were gross realized gains of $439 and gross realized losses of $99 from available-for-sale securities during the three months ended March 31, 2013. 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.
	The Company’s investments in debt securities are issued by GNMA and are backed by the full faith and credit of the U.S. government. These securities were purchased to satisfy applicable regulatory requirements of SPTC and have maturity dates which range from 2020 to 2043.
	Trading Securities
	The Company records all of its trading securities 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 Net gain from investments on the accompanying Consolidated Statements of Operations.
	Trading securities of the Company primarily consist of an investment related to the startup of mutual funds sponsored by LSV. These mutual funds are U.S. dollar denominated funds that invests primarily in securities of Canadian, Australian and Japanese companies as well as various other global securities. The underlying securities held by the funds are translated into U.S. dollars within the funds. The funds had a fair value of $4,914 and $4,849 at March 31, 2014 and December 31, 2013, respectively. There were no material gross realized gains or losses from the funds during the three months ended March 31, 2014 and 2013, 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 $21,153 and $21,133 at March 31, 2014 and December 31, 2013, respectively. There were no material net gains or losses from the change in fair value of the securities during the three months ended March 31, 2014 and 2013.

Lines_of_Credit

Lines of Credit	3 Months Ended
	Mar. 31, 2014
Line of Credit Facility [Abstract]	'
Lines of Credit	'
	Lines of Credit
	The Company has 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 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 agreement may be terminated. The Company had no borrowings under the Credit Facility at March 31, 2014. The Company was in compliance with all covenants of the Credit Facility during the three months ended March 31, 2014.
	The Company’s Canadian subsidiary has a credit facility agreement (the Canadian Credit Facility) for the purpose of facilitating the settlement of mutual fund transactions. The Canadian Credit Facility has no stated expiration date. The amount of the facility is limited to $2,000 Canadian dollars or the equivalent amount in U.S. dollars. The Canadian Credit Facility does not contain any covenants which restrict the liquidity or capital resources of the Company. The Company had no borrowings under the Canadian Credit Facility at March 31, 2014. The Company was in compliance with all covenants of the Canadian Credit Facility during the three months ended March 31, 2014.

Shareholders_Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
Shareholders' Equity	'
	Shareholders’ Equity
	Stock-Based Compensation
	The Company currently has one active equity compensation plan, the 2007 Equity Compensation Plan (the 2007 Plan), which provides for the grant of incentive stock options, non-qualified stock options and stock appreciation rights with respect to up to 20 million shares of common stock of the Company, subject to adjustment for stock splits, reclassifications, mergers and other events. Permitted grantees under the 2007 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 granted non-qualified stock options under the plan. All outstanding stock options have performance-based vesting provisions specific to each option grant that tie the vesting of the applicable stock options to the Company’s financial performance. The Company’s stock options vest at a rate of 50 percent when specified diluted earnings per share targets are achieved, and the remaining 50 percent when secondary, higher specified diluted earnings per share targets are achieved. The amount of stock-based compensation expense is based upon management’s estimate of when the earnings per share targets may be achieved.
	The Company discontinued any further grants under the Company’s 1998 Equity Compensation Plan (the 1998 Plan) as a result of the approval of the 2007 Plan. No options are available for grant from this plan. Grants made from the 1998 Plan continue in effect under the terms of the grant.
	The Company recognized stock-based compensation expense in its Consolidated Financial Statements in the three months ended March 31, 2014 and 2013, respectively, as follows:
		Three Months Ended March 31,
		2014			2013
	Stock-based compensation expense	$	2,823		$	5,293
	Less: Deferred tax benefit	(1,011		)	(1,916		)
	Stock-based compensation expense, net of tax	$	1,812		$	3,377
	As of March 31, 2014, there was approximately $36,019 of unrecognized compensation cost remaining, adjusted for estimated forfeitures, related to unvested employee stock options that management expects will vest and is being amortized.
	The Company issues new common shares associated with the exercise of stock options. The total intrinsic value of options exercised during the three months ended March 31, 2014 was $35,261. The total options exercisable as of March 31, 2014 had an intrinsic value of $179,917. The total intrinsic value for options exercisable is calculated as the difference between the market value of the Company’s common stock as of March 31, 2014 and the weighted average exercise price of the shares. The market value of the Company’s common stock as of March 31, 2014 was $33.61 as reported by the Nasdaq Stock Market, LLC. The weighted average exercise price of the options exercisable as of March 31, 2014 was $19.53. Total options that were outstanding and exercisable as of March 31, 2014 were 21,843,000 and 12,778,000, respectively.
	Common Stock Buyback
	The Company’s Board of Directors, under multiple authorizations, has authorized the repurchase of the Company’s common stock on the open market or through private transactions. The Company purchased 2,048,000 shares at a total cost of $69,002 during the three months ended March 31, 2014. The cost of stock purchases during the period includes the cost of certain transactions that settled in the following quarter. As of April 22, 2014, the Company has $212,068 of authorization remaining for the purchase of common stock under the program.
	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.

Accumulated_Comprehensive_Inco

Accumulated Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Accumulated Comprehensive Income (Loss)	'
	Accumulated Other Comprehensive Income
	The components of Accumulated other comprehensive income, net of tax, are as follows:
		Foreign			Unrealized			Total
		Currency			Gains (Losses)
		Translation			on Investments
		Adjustments
	Balance, January 1, 2014	$	101		$	1,386		$	1,487
	Other comprehensive income before reclassifications	(1,966		)	538			(1,428		)
	Amounts reclassified from accumulated other comprehensive income	—			(45		)	(45		)
	Net current-period other comprehensive income	(1,966		)	493			(1,473		)
	Balance, March 31, 2014	$	(1,865	)	$	1,879		$	14

Business_Segment_Information

Business Segment Information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Business Segment Information	'
	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.
	The information in the following tables is derived from the Company’s internal financial reporting used for corporate management purposes. There are no inter-segment revenues for the three months ended March 31, 2014 and 2013. Management evaluates Company assets on a consolidated basis during interim periods. The accounting policies of the reportable business segments are the same as those described in Note 1 to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
	The following tables highlight certain unaudited financial information about each of the Company’s business segments for the three months ended March 31, 2014 and 2013.
		Private			Investment			Institutional		Investment		Investments			Total
		Banks			Advisors			Investors		Managers		In New
												Businesses
		For the Three Months Ended March 31, 2014
	Revenues	$	105,179		$	66,424		$	68,657	$	61,008	$	1,118		$	302,386
	Expenses	100,190			34,577			34,095		39,184		4,249			212,295
	Operating profit (loss)	$	4,989		$	31,847		$	34,562	$	21,824	$	(3,131	)	$	90,091
	Gain on sale of subsidiary	5,582			—			—		—		—			5,582
	Total profit (loss)	$	10,571		$	31,847		$	34,562	$	21,824	$	(3,131	)	$	95,673
		Private			Investment			Institutional		Investment		Investments			Total
		Banks			Advisors			Investors		Managers		In New
												Businesses
		For the Three Months Ended March 31, 2013
	Revenues	$	98,746		$	55,191		$	63,162	$	53,820	$	960		$	271,879
	Expenses	96,298			31,625			31,509		35,162		3,738			198,332
	Operating profit (loss)	$	2,448		$	23,566		$	31,653	$	18,658	$	(2,778	)	$	73,547
	Gain on sale of subsidiary	22,112			—			—		—		—			22,112
	Total profit (loss)	$	24,560		$	23,566		$	31,653	$	18,658	$	(2,778	)	$	95,659
	A reconciliation of the total operating profit reported for the business segments to income from operations in the Consolidated Statements of Operations for the three months ended March 31, 2014 and 2013 is as follows:
		2014			2013
	Total operating profit from segments above	$	90,091		$	73,547
	Corporate overhead expenses	(11,699		)	(13,794		)
	Noncontrolling interest reflected in segments	—			289
	Income from operations	$	78,392		$	60,042
	The following tables provide additional information for the three months ended March 31, 2014 and 2013 pertaining to our business segments:
		Capital Expenditures						Depreciation
		2014			2013			2014		2013
	Private Banks	$	8,798		$	4,851		$	3,732	$	3,933
	Investment Advisors	3,589			1,775			491		509
	Institutional Investors	1,288			363			209		230
	Investment Managers	2,135			623			512		462
	Investments in New Businesses	580			88			530		454
	Total from business segments	$	16,390		$	7,700		$	5,474	$	5,588
	Corporate overhead	645			92			110		116
		$	17,035		$	7,792		$	5,584	$	5,704
		Amortization
		2014			2013
	Private Banks	$	5,952		$	5,336
	Investment Advisors	2,197			1,957
	Institutional Investors	341			302
	Investment Managers	227			202
	Investments in New Businesses	440			388
	Total from business segments	$	9,157		$	8,185
	Corporate overhead	57			57
		$	9,214		$	8,242

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The gross liability for unrecognized tax benefits at March 31, 2014 and December 31, 2013 was $12,683 and $12,028, respectively, exclusive of interest and penalties, of which $10,789 and $10,139 would affect the effective tax rate if the Company were to recognize the tax benefit.
	The Company classifies interest and penalties on unrecognized tax benefits as income tax expense. As of March 31, 2014 and December 31, 2013, the combined amount of accrued interest and penalties related to tax positions taken on tax returns was $825 and $754, respectively.
		March 31, 2014		December 31, 2013
	Gross liability for unrecognized tax benefits, exclusive of interest and penalties	$	12,683	$	12,028
	Interest and penalties on unrecognized benefits	825		754
	Total gross uncertain tax positions	$	13,508	$	12,782
	Amount included in Current liabilities	$	4,196	$	4,175
	Amount included in Other long-term liabilities	9,312		8,607
		$	13,508	$	12,782
	The Company’s effective tax rate was 35.9 percent and 34.9 percent for the three months ended March 31, 2014 and 2013, respectively. The increase in the 2014 tax rate was primarily due to the research and development tax credit. The Company's first quarter 2014 tax rate reflects no benefit for the tax credit due to the expiration of the credit on December 31, 2013, whereas the Company's first quarter 2013 tax rate reflects the benefit of the tax credit for 2012 and 2013.
	On January 2, 2013, the American Taxpayer Relief Act of 2012 (the Act) was signed into law which reinstated the research and development credit retroactively from January 1, 2012 through December 31, 2013. Current accounting guidance requires the determination of current and deferred taxes be based upon the provisions of the enacted tax law as of the balance sheet date. Since the Act was not signed into law until January 2, 2013, the effect of the 2012 research and development tax credit was therefore reflected in the Company's 2013 tax rate. Since the research and development tax credit expired as of December 31, 2013, no credit was reflected in the Company's 2014 tax rate. The increase in tax rate was partially offset by an increase in the portion of pre-tax income in certain foreign jurisdictions which is taxed at a lower rate during the three months ended March 31, 2014.
	The Company files income tax returns in the United States on a consolidated basis and in many U.S. state and foreign jurisdictions. The Company is subject to examination of income tax returns by the Internal Revenue Service (IRS) and other domestic and foreign tax authorities. The Company is no longer subject to U.S. federal income tax examination for years before 2010 and is no longer subject to state, local or foreign income tax examinations by authorities for years before 2007.
	The Company estimates it will recognize $4,196 of unrecognized tax benefits within the next twelve months due to the expiration of the statute of limitations and resolution of income tax audits. These unrecognized tax benefits are related to tax positions taken on certain federal, state, and foreign tax returns. However, the timing of the resolution of income tax examinations is highly uncertain, and the amounts ultimately paid, if any, upon resolution of the issues raised by the taxing authorities may differ materially from the amounts accrued for each year. While it is reasonably possible that some issues under examination could be resolved in the next twelve months, based upon the current facts and circumstances, the Company cannot reasonably estimate the timing of such resolution or total range of potential changes as it relates to the current unrecognized tax benefits that are recorded as part of the Company’s financial statements.

Commitments_And_Contingencies

Commitments And Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments And Contingencies	'
	Commitments and Contingencies
	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, State of Louisiana. One of the five actions purports to set forth claims on behalf of a class and also names SPTC as a defendant and, as described below, was certified as a class in December 2012. 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 SPTC under the Louisiana Securities Act. The class action originally included a claim against SEI and SPTC for an alleged violation of the Louisiana Unfair Trade Practices Act. Two of the other 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, State of Louisiana, 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 the actions are purportedly related to the 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.
	Two of the five actions filed in East Baton Rouge were removed to federal court and transferred by the Judicial Panel on Multidistrict Litigation to United States District Court for the Northern District of Texas. On August 31, 2011, the United States District Court for the Northern District of Texas issued an order and judgment that the causes of action alleged against SEI in the two removed actions were preempted by federal law and the court dismissed these cases with prejudice. Plaintiffs appealed this ruling, and on March 19, 2012, a panel of the Court of Appeals for the Fifth Circuit reversed the decision of the United States District Court and remanded the actions for further proceedings. On July 18, 2012, SEI filed a petition for a writ of certiorari in the United States Supreme Court, seeking review of the decision by the United States Court of Appeals in the Fifth Circuit to permit the claims against SEI to proceed. SEI believes that the trial court correctly concluded that the claims against SEI were barred by the federal Securities Litigation Uniform Standards Act and requested that the Supreme Court reinstate that dismissal. On January 18, 2013, the Supreme Court granted the petition for a writ of certiorari. On October 7, 2013, the Supreme Court heard oral argument on the appeal and on February 26, 2014 the Supreme Court affirmed the judgment of the Court of Appeals.
	The case filed in Ascension was also removed to federal court and transferred by the Judicial Panel on Multidistrict Litigation to the Northern District of Texas. The schedule for responding to that complaint has not yet been established. The plaintiffs in the remaining two cases in East Baton Rouge have granted SEI and SPTC an extension to respond to the filings. SEI and SPTC filed exceptions in the class action pending in East Baton Rouge, which the Court granted in part and dismissed the claims under the Louisiana Unfair Trade Practices Act and denied in part as to the other exceptions.
	SEI and SPTC filed an answer to the East Baton Rouge class action, plaintiffs filed a motion for class certification; and SEI and SPTC also filed a motion for summary judgment against certain named plaintiffs which the Court stated would not be set for hearing until after the hearing on the class certification motion. The Court in the East Baton Rouge action held a hearing on class certification on September 20, 2012. By oral decision on December 5, 2012 and later entered in a judgment signed on December 17, 2012 that was subsequently amended, the Court in East Baton Rouge certified a class to be composed of persons who purchased any Stanford International Bank certificates of deposit (SIB CDs) in Louisiana between January 1, 2007 and February 13, 2009; persons who renewed any SIB CD 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. On January 30, 2013, SEI and SPTC filed motions for appeal from the judgments that stated SEI's and SPTC's intention to move to stay the litigation. On February 1, 2013, plaintiffs filed a motion for Leave to File First Amended and Restated Class Action Petition in which they ask the Court to allow them to amend the petition in this case to add additional facts that were developed during discovery and adding 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 15, 2013, SEI filed a motion for new trial, or, in the alternative, for reconsideration of the Court's order allowing amendment. On February 22, 2013, SEI filed a motion to stay proceedings in view of the pending Supreme Court case. On February 28, 2013, SEI responded to the First Amended and Restated Class Action Petition by filing an exception. On March 11, 2013, the insurance carrier defendants filed a notice of removal removing the case to the Middle District of Louisiana and on March 18, 2013, the insurance carrier defendants filed answers. On March 13, 2013, SEI notified the Judicial Panel on Multidistrict Litigation (MDL) of this case as a potential tag-along action. On March 19, 2013, plaintiffs filed a motion to remand, a motion for expedited briefing schedule, expedited status conference and expedited consideration of their motion to remand, a motion for leave to file under seal and a motion for order pursuant to 28 U.S.C. 1447(b) requiring removing defendants to supplement federal court record with certified copy of state court record. These motions are now fully briefed. On March 25, 2013, SEI filed a motion that the court decline to adopt the state court's order regarding class certification, which the court dismissed without prejudice to renew upon a determination of removal jurisdiction in an April 12, 2013 order that also dismissed without prejudice a motion to dismiss for lack of jurisdiction and improper venue filed on April 9, 2013 by one of the insurers. On April 1, 2013, the Louisiana Office of Financial Institutions (OFI) filed a motion to remand and sever claims, and a response to that motion by the insurers and opposition to that motion by the plaintiffs were filed on April 22, 2013. Along with the briefing in the Middle District of Louisiana, on March 13, 2013, SEI notified the MDL of this case as a potential tag-along action. On March 19, 2013, plaintiffs notified the MDL that they had filed a motion to remand and asked the panel to decline to issue a conditional transfer order. On March 29, 2013, the MDL issued a conditional transfer order (CTO). On April 18, 2013, OFI filed a motion to vacate the CTO or, in the alternative, stay any ruling to transfer the matter until after the Middle District of Louisiana ruled on OFI's motion to remand and sever. Plaintiffs filed a motion to vacate the CTO on April 19, 2013. SEI's responses to those motions were filed on May 9, 2013. On June 12, 2013, the MDL Panel issued an order notifying the parties that on July 25, 2013, it would consider, without oral argument, Plaintiffs' and OFI's motions to vacate the CTO. On August 7, 2013, the MDL Panel affirmed the CTO and transferred the matter against SEI to the United States District Court for the Northern District of Texas; the MDL Panel also severed the claims against OFI and remanded those claims to the Middle District of Louisiana. On September 11, 2013, defendants filed a motion requesting a status conference with the Court to address the status of all pending motions. On October 4, 2013, Plaintiffs filed a petition for a writ of mandamus asking the United States Court of Appeals for the Fifth Circuit to review the MDL Panel’s transfer Order and on February 14, 2014, the Court denied the petition.
	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 (SIMC) was filed against SIMC in the United States District Court for the Eastern District of Pennsylvania on December 11, 2013. The plaintiffs bring the case as a shareholder derivative action against SIMC 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 for an alleged breach of fiduciary duty with respect to compensation received by the adviser. The plaintiffs have brought the suit against SIMC 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 plaintiffs seek: (1) damages for the funds in the amount of the alleged “excessive” fees earned by SIMC beginning from the one year period prior to the filing of the lawsuit, plus interest, costs, and fees; (2) orders declaring that SIMC allegedly violated Section 36(b) and enjoining SIMC from further alleged violations; and (3) rescission of the advisory contracts between SIMC and 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 February 24, 2014, SIMC filed a motion to dismiss the complaint in this lawsuit. While the outcome of this litigation is uncertain given its early phase, SIMC believes that it has valid defenses to plaintiffs' claims and intends to defend the lawsuit vigorously and SIMC is not reasonably able to provide an estimate of the ultimate loss, if any, with respect to this lawsuit.

Sale_of_SEI_Asset_Korea

Sale of SEI Asset Korea	3 Months Ended
	Mar. 31, 2014
Disposal Group, Not Discontinued Operation, Disposal Disclosures [Abstract]	'
Sale of SEI Asset Korea	'
	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 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 Asset Management Limited. 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 the three months ended March 31, 2013 as a result of the sale. 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, with respect to the one-year period ended December 31, 2013 during the three months ended March 31, 2014. The Company received the payment for this portion of the contingent purchase price in April 2014. This amount is included in Receivables on the Consolidated Balance Sheet as of March 31, 2014. 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
	Revenues	$	2,889
	Net income	$	796
	Less: Income attributable to the noncontrolling interests	(350		)
	Net income attributable to SEI AK	$	446

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Basis of Presentation	'
	Basis of Presentation
	The accompanying Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States of America. Certain financial information and accompanying note disclosure normally included in the Company’s Annual Report on Form 10-K has been condensed or omitted. The interim financial information is unaudited but reflects all adjustments (consisting of only normal recurring adjustments) which are, in the opinion of management, necessary for a fair statement of financial position of the Company as of March 31, 2014, the results of operations for the three months ended March 31, 2014 and 2013, and cash flows for the three month periods ended March 31, 2014 and 2013. These interim Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements and the Notes to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
	There have been no significant changes in significant accounting policies during the three months ended March 31, 2014 as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
Reclassifications	'
	Reclassifications
	Certain prior year amounts have been reclassified to conform to current year presentation.
Cash and Cash Equivalents	'
	Statements of Cash Flows
	For purposes of the Consolidated Statements of Cash Flows, the Company considers investment instruments purchased with an original maturity of three months or less to be cash equivalents.
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 total partnership interest in LSV was approximately 39.3 percent and 39.8 percent during the three months ended March 31, 2014 and 2013, respectively. 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.
Variable Interest Entities	'
	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 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, is not 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 not significant. 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 not significant to the total assets of the Company.
Fair Value of Financial Instruments	'
	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 equity and fixed-income mutual funds that are quoted daily. Level 2 financial assets consist of Government National Mortgage Association (GNMA) mortgage-backed pass-through certificates, Federal Home Loan Bank (FHLB) and other U.S. government agency short-term notes and investment grade commercial paper. The Company's Level 2 financial assets, with the exception of the GNMA securities, were purchased as part of a cash management program requiring only short term, top-tier investment grade government and corporate securities. The GNMA mortgage-backed pass-through certificates were purchased for the sole purpose of satisfying specific regulatory requirements imposed on our wholly-owned limited purpose federal thrift subsidiary, SEI Private Trust Company (SPTC). As a result, the Company's Level 2 financial assets are limited to only these types of fixed income securities. The valuation of the Company's Level 2 financial assets are based upon securities pricing policies and procedures utilized by third-party pricing vendors. The pricing policies and procedures applied during the three months ended March 31, 2014 were consistent with those as described in our Annual Report on Form 10-K at December 31, 2013.
Available-for-sale Securities	'
	These net unrealized gains are reported as a separate component of Accumulated other comprehensive income on the accompanying Consolidated Balance Sheets.
Trading Securities	'
	The Company records all of its trading securities 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 Net gain from investments on the accompanying Consolidated Statements of Operations.
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.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Calculation Of Basic And Diluted Earnings Per Share	'
	The calculations of basic and diluted earnings per share for the three months ended March 31, 2014 and 2013 are:
		For the Three Months Ended March 31, 2014
		Income			Shares			Per Share
		(Numerator)			(Denominator)			Amount
	Basic earnings per common share	$	74,820		169,306,000			$	0.44
	Dilutive effect of stock options	—			4,522,000
	Diluted earnings per common share	$	74,820		173,828,000			$	0.43
		For the Three Months Ended March 31, 2013
		Income			Shares			Per Share
		(Numerator)			(Denominator)			Amount
	Basic earnings per common share	$	71,920		172,598,000			$	0.42
	Dilutive effect of stock options	—			3,407,000
	Diluted earnings per common share	$	71,920		176,005,000			$	0.41
Adjustments To Reconcile Net Income To Net Cash Provided By Operating Activities	'
	The following table provides the details of the adjustments to reconcile net income to net cash provided by operating activities for the three months ended March 31:
		2014			2013
	Net income	$	74,820		$	72,270
	Adjustments to reconcile net income to net cash provided by operating activities:
	Depreciation	5,584			5,704
	Amortization	9,214			8,242
	Equity in earnings of unconsolidated affiliates	(31,891		)	(27,588		)
	Distributions received from unconsolidated affiliate	31,505			27,821
	Stock-based compensation	2,823			5,293
	Provision for losses on receivables	(25		)	216
	Deferred income tax expense	4,686			(7,730		)
	Gain from sale of SEI AK	(5,582		)	(22,112		)
	Net gain from investments	(136		)	(280		)
	Change in other long-term liabilities	705			368
	Change in other assets	(3,273		)	2,832
	Other	(1,901		)	(7,996		)
	Change in current asset and liabilities
	Decrease (increase) in
	Restricted cash for broker-dealer operations	—			500
	Receivables from regulated investment companies	(3,908		)	(5,473		)
	Receivables	(15,453		)	(9,127		)
	Other current assets	(3,266		)	(2,466		)
	Increase (decrease) in
	Accounts payable	(7,862		)	(4,618		)
	Accrued liabilities	(12,199		)	4,571
	Deferred revenue	101			(952		)
	Total adjustments	(30,878		)	(32,795		)
	Net cash provided by operating activities	$	43,942		$	39,475

Investment_In_Unconsolidated_A1

Investment In Unconsolidated Affiliates (Tables)	3 Months Ended
	Mar. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]	'
Condensed Statement of Operations of LSV	'
	The following table contains the condensed statements of operations of LSV for the three months ended March 31, 2014 and 2013:
		Three Months Ended March 31,
		2014		2013
	Revenues	$	95,773	$	80,916
	Net income	81,923		70,180

Composition_of_Certain_Financi1

Composition of Certain Financial Statement Captions (Tables)	3 Months Ended
	Mar. 31, 2014
Items Included in Consolidated Statement of Financial Condition [Abstract]	'
Receivables	'
	Receivables on the accompanying Consolidated Balance Sheets consist of:
		March 31, 2014			December 31, 2013
	Trade receivables	$	56,596		$	44,502
	Fees earned, not billed	136,956			128,248
	Other receivables	14,798			14,565
		208,350			187,315
	Less: Allowance for doubtful accounts	(626		)	(651		)
		$	207,724		$	186,664
Property And Equipment	'
	Property and Equipment on the accompanying Consolidated Balance Sheets consists of:
		March 31, 2014			December 31, 2013
	Buildings	$	138,437		$	138,426
	Equipment	71,838			70,117
	Land	9,997			9,929
	Purchased software	98,472			96,268
	Furniture and fixtures	17,081			17,060
	Leasehold improvements	5,173			4,670
	Construction in progress	5,638			2,589
		346,636			339,059
	Less: Accumulated depreciation	(225,597		)	(220,064		)
	Property and Equipment, net	$	121,039		$	118,995
Accrued Liabilities	'
	Accrued liabilities on the accompanying Consolidated Balance Sheets consist of:
		March 31, 2014			December 31, 2013
	Accrued employee compensation	$	29,353		$	69,256
	Accrued employee benefits and other personnel	5,683			9,647
	Accrued consulting, outsourcing and professional fees	23,475			19,311
	Accrued sub-advisory, distribution and other asset management fees	25,050			25,018
	Accrued income taxes	26,922			—
	Accrued dividend payable	—			37,314
	Other accrued liabilities	31,181			27,577
	Total accrued liabilities	$	141,664		$	188,123

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 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:
		At March 31, 2014
		Fair Value Measurements at Reporting Date Using
	Assets	Total		Quoted Prices		Significant
				in		Other
				Active  Markets		Observable
				for Identical		Inputs
				Assets		(Level 2)
				(Level 1)
	Equity available-for-sale securities	$	11,713	$	11,713	$	—
	Fixed income available-for-sale securities	69,947		—		69,947
	Fixed income securities owned	21,153		—		21,153
	Trading securities	4,914		4,914		—
		$	107,727	$	16,627	$	91,100
		At December 31, 2013
		Fair Value Measurements at Reporting Date Using
	Assets	Total		Quoted Prices		Significant
				in		Other
				Active  Markets		Observable
				for Identical		Inputs
				Assets		(Level 2)
				(Level 1)
	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
	Trading securities	4,849		4,849		—
		$	109,305	$	16,482	$	92,823

Marketable_Securities_Tables

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2014
Marketable Securities [Abstract]	'
Investments Available For Sale	'
	Investments available for sale classified as non-current assets consist of:
		At March 31, 2014
		Cost		Gross		Gross		Fair
		Amount		Unrealized		Unrealized		Value
				Gains		Losses
	SEI-sponsored mutual funds	$	7,559	$	1,363	$	—	$	8,922
	Equities and other mutual funds	2,719		72		—		2,791
	Debt securities	68,803		1,144		—		69,947
		$	79,081	$	2,579	$	—	$	81,660
		At December 31, 2013
		Cost		Gross		Gross		Fair
		Amount		Unrealized		Unrealized		Value
				Gains		Losses
	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

Shareholders_Equity_Tables

Shareholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]	'
	The Company recognized stock-based compensation expense in its Consolidated Financial Statements in the three months ended March 31, 2014 and 2013, respectively, as follows:
		Three Months Ended March 31,
		2014			2013
	Stock-based compensation expense	$	2,823		$	5,293
	Less: Deferred tax benefit	(1,011		)	(1,916		)
	Stock-based compensation expense, net of tax	$	1,812		$	3,377

Accumulated_Comprehensive_Inco1

Accumulated Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Schedule Of Accumulated Other Comprehensive Income (Loss), Net Of Tax	'
	The components of Accumulated other comprehensive income, net of tax, are as follows:
		Foreign			Unrealized			Total
		Currency			Gains (Losses)
		Translation			on Investments
		Adjustments
	Balance, January 1, 2014	$	101		$	1,386		$	1,487
	Other comprehensive income before reclassifications	(1,966		)	538			(1,428		)
	Amounts reclassified from accumulated other comprehensive income	—			(45		)	(45		)
	Net current-period other comprehensive income	(1,966		)	493			(1,473		)
	Balance, March 31, 2014	$	(1,865	)	$	1,879		$	14

Business_Segment_Information_T

Business Segment Information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Schedule Of Financial Information About Business Segments	'
	The following tables highlight certain unaudited financial information about each of the Company’s business segments for the three months ended March 31, 2014 and 2013.
		Private			Investment			Institutional		Investment		Investments			Total
		Banks			Advisors			Investors		Managers		In New
												Businesses
		For the Three Months Ended March 31, 2014
	Revenues	$	105,179		$	66,424		$	68,657	$	61,008	$	1,118		$	302,386
	Expenses	100,190			34,577			34,095		39,184		4,249			212,295
	Operating profit (loss)	$	4,989		$	31,847		$	34,562	$	21,824	$	(3,131	)	$	90,091
	Gain on sale of subsidiary	5,582			—			—		—		—			5,582
	Total profit (loss)	$	10,571		$	31,847		$	34,562	$	21,824	$	(3,131	)	$	95,673
		Private			Investment			Institutional		Investment		Investments			Total
		Banks			Advisors			Investors		Managers		In New
												Businesses
		For the Three Months Ended March 31, 2013
	Revenues	$	98,746		$	55,191		$	63,162	$	53,820	$	960		$	271,879
	Expenses	96,298			31,625			31,509		35,162		3,738			198,332
	Operating profit (loss)	$	2,448		$	23,566		$	31,653	$	18,658	$	(2,778	)	$	73,547
	Gain on sale of subsidiary	22,112			—			—		—		—			22,112
	Total profit (loss)	$	24,560		$	23,566		$	31,653	$	18,658	$	(2,778	)	$	95,659
Reconciliation Of Total Operating Profit Reported For Business Segments To Income From Operations In Consolidated Statements Of Operations	'
	A reconciliation of the total operating profit reported for the business segments to income from operations in the Consolidated Statements of Operations for the three months ended March 31, 2014 and 2013 is as follows:
		2014			2013
	Total operating profit from segments above	$	90,091		$	73,547
	Corporate overhead expenses	(11,699		)	(13,794		)
	Noncontrolling interest reflected in segments	—			289
	Income from operations	$	78,392		$	60,042
Reconciliation of Other Significant Reconciling Items from Segments to Consolidated [Table Text Block]	'
	The following tables provide additional information for the three months ended March 31, 2014 and 2013 pertaining to our business segments:
		Capital Expenditures						Depreciation
		2014			2013			2014		2013
	Private Banks	$	8,798		$	4,851		$	3,732	$	3,933
	Investment Advisors	3,589			1,775			491		509
	Institutional Investors	1,288			363			209		230
	Investment Managers	2,135			623			512		462
	Investments in New Businesses	580			88			530		454
	Total from business segments	$	16,390		$	7,700		$	5,474	$	5,588
	Corporate overhead	645			92			110		116
		$	17,035		$	7,792		$	5,584	$	5,704
		Amortization
		2014			2013
	Private Banks	$	5,952		$	5,336
	Investment Advisors	2,197			1,957
	Institutional Investors	341			302
	Investment Managers	227			202
	Investments in New Businesses	440			388
	Total from business segments	$	9,157		$	8,185
	Corporate overhead	57			57
		$	9,214		$	8,242

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Schedule Of Interest And Penalties	'
		March 31, 2014		December 31, 2013
	Gross liability for unrecognized tax benefits, exclusive of interest and penalties	$	12,683	$	12,028
	Interest and penalties on unrecognized benefits	825		754
	Total gross uncertain tax positions	$	13,508	$	12,782
	Amount included in Current liabilities	$	4,196	$	4,175
	Amount included in Other long-term liabilities	9,312		8,607
		$	13,508	$	12,782

Sale_of_SEI_Asset_Korea_Sale_o

Sale of SEI Asset Korea Sale of SEI Asset Korea (Tables)	3 Months Ended
	Mar. 31, 2014
Disposal Group, Not Discontinued Operation, Disposal Disclosures [Abstract]	'
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]	'
	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
	Revenues	$	2,889
	Net income	$	796
	Less: Income attributable to the noncontrolling interests	(350		)
	Net income attributable to SEI AK	$	446

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Cash and cash equivalents	$545,552	$452,099	$578,273	$452,247
Additions to capitalized software	-9,408	-6,048	'	'
Net book value of the Platform	312,866	'	312,615	'
Capitalized software, accumulated amortization	189,219	'	180,062	'
Anti-dilutive employee stock options	4,389,000	6,863,000	'	'
Antidilutive securities excluded from computation of net income, per outstanding unit, amount	$32.40	$28.05	'	'
SEI Investments Distribution Co. (SIDCO) [Member]	'	'	'	'
Restricted cash	500	'	500	'
SEI Investments (Europe) Limited [Member]	'	'	'	'
Restricted cash	5,000	'	5,000	'
SEI-Sponsored Open-Ended Money Market Mutual Funds [Member]	'	'	'	'
Cash and cash equivalents	368,882	'	387,201	'
Software Development [Member]	'	'	'	'
Amortization expense related to capitalized software	9,157	8,186	'	'
SEI Wealth Platform [Member]	'	'	'	'
Finite-Lived Intangible Asset, Useful Life	'15 years	'	'	'
Amortization expense related to capitalized software	9,110	8,068	'	'
Net book value of the Platform	312,819	'	'	'
Capitalized software, accumulated amortization	159,034	'	'	'
Capitalized software development costs in-progress associated with future releases	$12,204	'	'	'
Weighted Average [Member] | Software Development [Member]	'	'	'	'
Finite-Lived Intangible Asset, Useful Life	'	'8 years 3 months	'	'
Weighted Average [Member] | SEI Wealth Platform [Member]	'	'	'	'
Finite-Lived Intangible Asset, Useful Life	'	'8 years 3 months	'	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Calculation Of Basic And Diluted Earnings Per Share) (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Accounting Policies [Abstract]	'	'
Basic earnings per common share, Income (Numerator)	$74,820	$71,920
Shares used to compute basic earnings per share	169,306	172,598
Basic earnings per common share	$0.44	$0.42
Dilutive effect of stock options, income	0	0
Dilutive effect of stock options, shares	4,522	3,407
Diluted earnings per common share, Income (Numerator)	$74,820	$71,920
Shares used to compute diluted earnings per share	173,828	176,005
Diluted earnings per common share	$0.43	$0.41

Summary_of_Significant_Account5

Summary of Significant Accounting Policies (Adjustments To Reconcile Net Income To Net Cash Provided By Operating Activities) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Accounting Policies [Abstract]	'	'
Net income	$74,820	$72,270
Depreciation	5,584	5,704
Amortization	9,214	8,242
Equity in earnings of unconsolidated affiliates	-31,891	-27,588
Distributions received from unconsolidated affiliate	31,505	27,821
Stock-based compensation	2,823	5,293
Provision for losses on receivables	-25	216
Deferred income tax expense	4,686	-7,730
Gain on sale of SEI AK	-5,582	-22,112
Net gain from investments	-136	-280
Change in other long-term liabilities	705	368
Change in other assets	-3,273	2,832
Other	-1,901	-7,996
Decrease (increase) in Restricted cash for broker-dealer operations	0	500
Decrease (increase) in Receivables from regulated investment companies	-3,908	-5,473
Decrease (increase) in Receivables	-15,453	-9,127
Decrease (increase) in Other current assets	-3,266	-2,466
Increase (decrease) in Accounts payable	-7,862	-4,618
Increase (decrease) in Accrued liabilities	-12,199	4,571
Increase (decrease) in Deferred revenue	101	-952
Total adjustments	-30,878	-32,795
Net cash provided by operating activities	$43,942	$39,475

Investment_In_Unconsolidated_A2

Investment In Unconsolidated Affiliates (Narrative) (Details) (USD $)

3 Months Ended

3 Months Ended

3 Months Ended

In Thousands, unless otherwise specified

Mar. 31, 2014

Mar. 31, 2013

Apr. 22, 2014

Apr. 30, 2011

Oct. 31, 2012

Oct. 31, 2012

Apr. 22, 2014

Apr. 22, 2014

Apr. 30, 2011

Apr. 22, 2014

Oct. 31, 2012

Apr. 22, 2014

Mar. 31, 2014

Mar. 31, 2013

Apr. 30, 2013

Mar. 31, 2012

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

LSV Employee Group II [Member]

LSV Employee Group II [Member]

LSV Employee Group III [Member]

Financial Guarantee [Member]

Financial Guarantee [Member]

Financial Guarantee [Member]

Financial Guarantee [Member]

Financial Guarantee [Member]

Financial Guarantee [Member]

Financial Guarantee [Member]

L S V Asset Management [Member]

L S V Asset Management [Member]

L S V Asset Management [Member]

L S V Asset Management [Member]

Gao Fu [Member]

Gao Fu [Member]

Maximum [Member]

L S V Asset Management [Member]

L S V Asset Management [Member]

LSV Employee Group II [Member]

LSV Employee Group II [Member]

LSV Employee Group III [Member]

LSV Employee Group III [Member]

LSV Employee Group III [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Investments in and Advances to Affiliates [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity method investment, ownership percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

39.30%

39.80%

'

'

50.00%

Total investment in equity method investee

'

'

'

'

'

'

'

'

'

'

'

'

$51,306

'

'

'

$10,450

'

'

Investment in equity method investee in excess of the underlying equity in net assets

'

'

'

'

'

'

'

'

'

'

'

'

3,062

'

'

'

'

'

'

Distributions received from unconsolidated affiliate

31,505

27,821

'

'

'

'

'

'

'

'

'

'

31,505

27,821

'

'

'

'

'

Company's share in the earnings of equity method investee

31,891

27,588

'

'

'

'

'

'

'

'

'

'

32,216

27,806

'

'

-325

-218

'

Purchase price paid for partnership interest in LSV

'

'

'

4,300

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Guarantor Obligations, Maximum Exposure, Undiscounted

'

'

'

'

'

24,930

6,374

'

3,655

'

45,000

45,000

'

'

'

'

'

'

'

Unpaid Principal Balance

'

'

365

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Guarantor Obligations, Current Carrying Value

'

'

'

'

'

'

'

0

'

0

'

'

'

'

'

'

'

'

'

Purchase of Partnership Interest Value

'

'

'

'

77,700

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loans Payable

'

'

'

'

$69,930

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Investment_In_Unconsolidated_A3

Investment In Unconsolidated Affiliates (Condensed Statement Of Operations Of LSV) (Details) (L S V Asset Management [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
L S V Asset Management [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Equity Method Investment, Summarized Financial Information, Revenue	$95,773	$80,916
Equity Method Investment, Summarized Financial Information, Net Income (Loss)	$81,923	$70,180

Variable_Interest_Entities_Inv1

Variable Interest Entities - Investment Products (Details)	3 Months Ended
	Mar. 31, 2014
Variable Interest Entities - Investment Products [Abstract]	'
Percentage not approached by expected return on any VIE investment	50.00%

Composition_of_Certain_Financi2

Composition of Certain Financial Statement Captions (Receivables) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Items Included in Consolidated Statement of Financial Condition [Abstract]	'	'
Trade receivables	$56,596	$44,502
Fees earned, not billed	136,956	128,248
Other receivables	14,798	14,565
Receivables, Gross, Current	208,350	187,315
Less: Allowance for doubtful accounts	626	651
Receivables, net	$207,724	$186,664

Composition_of_Certain_Financi3

Composition of Certain Financial Statement Captions (Property And Equipment) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Property, Plant and Equipment [Line Items]	'	'	'
Property and Equipment, gross	$346,636	'	$339,059
Less: Accumulated depreciation	-225,597	'	-220,064
Property and Equipment, net	121,039	'	118,995
Depreciation expense	5,584	5,704	'
Building [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property and Equipment, gross	138,437	'	138,426
Equipment [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property and Equipment, gross	71,838	'	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	98,472	'	96,268
Furniture and Fixtures [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property and Equipment, gross	17,081	'	17,060
Leasehold Improvements [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property and Equipment, gross	5,173	'	4,670
Construction in Progress [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property and Equipment, gross	$5,638	'	$2,589

Composition_of_Certain_Financi4

Composition of Certain Financial Statement Captions (Accrued Liabilities) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Items Included in Consolidated Statement of Financial Condition [Abstract]	'	'
Accrued employee compensation	$29,353	$69,256
Accrued employee benefits and other personnel	5,683	9,647
Accrued consulting, outsourcing and professional fees	23,475	19,311
Accrued sub-advisory, distribution and other asset management fees	25,050	25,018
Accrued income taxes	26,922	0
Accrued dividend payable	0	37,314
Other accrued liabilities	31,181	27,577
Total accrued liabilities	$141,664	$188,123

Fair_Value_Measurements_Fair_V

Fair Value Measurements (Fair Value Of Certain Financial Assets And Liabilities) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Fixed income securities owned	$21,153	$21,133
Trading securities	4,914	4,849
Estimate of Fair Value Measurement [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Equity available-for-sale securities	11,713	11,633
Fixed income available-for-sale securities	69,947	71,690
Fixed income securities owned	21,153	21,133
Trading securities	4,914	4,849
Assets, fair value	107,727	109,305
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Equity available-for-sale securities	11,713	11,633
Fixed income available-for-sale securities	0	0
Fixed income securities owned	0	0
Trading securities	4,914	4,849
Assets, fair value	16,627	16,482
Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Equity available-for-sale securities	0	0
Fixed income available-for-sale securities	69,947	71,690
Fixed income securities owned	21,153	21,133
Trading securities	0	0
Assets, fair value	$91,100	$92,823

Marketable_Securities_Narrativ

Marketable Securities (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Schedule of Investments [Line Items]	'	'	'
Net unrealized gains	$1,879	'	$1,386
Unrealized gains during the period, income tax expense	700	'	430
Available-for-sale securities, gross realized gains	119	439	'
Available-for-sale securities, gross realized losses	49	99	'
Trading securities	4,914	'	4,849
Securities owned	21,153	'	21,133
Trading Securities [Member]	'	'	'
Schedule of Investments [Line Items]	'	'	'
Trading securities	$4,914	'	$4,849

Marketable_Securities_Investme

Marketable Securities (Investments Available For Sale) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment Available for Sale, Cost Amount	$79,081	$81,507
Investment Available for Sale, Gross Unrealized Gains	2,579	1,816
Investment Available for Sale, Gross Unrealized Losses	0	0
Investment Available for Sale, Fair Value	81,660	83,323
SEI-Sponsored Mutual Funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment Available for Sale, Cost Amount	7,559	7,612
Investment Available for Sale, Gross Unrealized Gains	1,363	1,242
Investment Available for Sale, Gross Unrealized Losses	0	0
Investment Available for Sale, Fair Value	8,922	8,854
Equity Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment Available for Sale, Cost Amount	2,719	2,615
Investment Available for Sale, Gross Unrealized Gains	72	164
Investment Available for Sale, Gross Unrealized Losses	0	0
Investment Available for Sale, Fair Value	2,791	2,779
Debt Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment Available for Sale, Cost Amount	68,803	71,280
Investment Available for Sale, Gross Unrealized Gains	1,144	410
Investment Available for Sale, Gross Unrealized Losses	0	0
Investment Available for Sale, Fair Value	$69,947	$71,690

Lines_of_Credit_Details

Lines of Credit (Details) (Line of Credit [Member])	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014
	2012 Credit Facility [Member]	2012 Credit Facility [Member]	Canadian Subsidiary [Member]
	USD ($)	London Interbank Offered Rate (LIBOR) [Member]	CAD
Line of Credit Facility [Line Items]	'	'	'
Debt Instrument, Term	'5 years	'	'
Credit facility maximum borrowing capacity	$300,000	'	2,000
Credit facility expiration date	2-Feb-17	'	'
Credit facility variable interest rate basis spread	'	1.25%	'
Credit facility commitment fee per annum on daily unused portion	0.15%	'	'
Aggregate amount that may increase under credit facility	$100,000	'	'

Shareholders_Equity_Narrative_

Shareholders' Equity (Narrative) (Details) (USD $)	0 Months Ended	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Apr. 22, 2014	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Unrecognized compensation cost	'	$36,019
Total intrinsic value of options exercised	'	35,261
Aggregate intrinsic value of options exercisable	'	179,917
Share Price	'	$33.61
Weighted average exercise price per share	'	$19.53
Total options that were outstanding	'	21,843,000
Total options that were exercisable	'	12,778,000
Common Stock Buyback [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Shares purchased and retired	'	2,048,000
Company purchased, cost	'	69,002
Remaining stock repurchase authorization amount	$212,068	'
2007 Plan [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Number of active equity compensation plans	'	1
Number of shares available for grant	'	20,000,000
2007 Plan [Member] | Tranche One [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Vesting rate	'	50.00%
2007 Plan [Member] | Tranche Two [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Vesting rate	'	50.00%

Shareholders_Equity_StockBased

Shareholders' Equity (Stock-Based Compensation Expense) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Stockholders' Equity Note [Abstract]	'	'
Stock-based compensation expense	$2,823	$5,293
Less: Deferred tax benefit	-1,011	-1,916
Stock-based compensation expense, net of tax	$1,812	$3,377

Accumulated_Comprehensive_Inco2

Accumulated Comprehensive Income (Loss) (Schedule Of Accumulated Other Comprehensive Income (Loss), Net Of Tax) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Accumulated other comprehensive income (loss), Unrealized Holding Gains (Losses) on Investments	$1,879	'	$1,386
Accumulated Other Comprehensive Income (Loss)	14	'	1,487
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	-1,966	'	'
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Reclassification Adjustments, Net of Tax	538	'	'
Other Comprehensive Income (Loss) before Reclassification, Net of Tax	-1,428	'	'
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	0	'	'
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	45	221	'
Other Comprehensive Income (Loss) Reclassification Adjustment, Net of Tax	45	'	'
Total comprehensive loss, Foreign Currency Translation Adjustments	-1,966	-5,307	'
Total comprehensive loss, Unrealized Holding Gains (Losses) on Investments	493	'	'
Total other comprehensive loss, net of tax	-1,473	-5,407	'
SEI Investments Company [Member]	'	'	'
Accumulated other comprehensive income (loss), Foreign Currency Translation Adjustments	-1,865	'	101
Accumulated other comprehensive income (loss), Unrealized Holding Gains (Losses) on Investments	1,879	'	1,386
Accumulated Other Comprehensive Income (Loss)	$14	'	$1,487

Business_Segment_Information_S

Business Segment Information (Schedule Of Financial Information About Business Segments) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Revenues	$302,386	$271,879
Expenses	212,295	198,332
Operating profit (loss)	90,091	73,547
Gain on sale of subsidiary	5,582	22,112
Total profit (loss)	95,673	95,659
Private Banks [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	105,179	98,746
Expenses	100,190	96,298
Operating profit (loss)	4,989	2,448
Gain on sale of subsidiary	5,582	22,112
Total profit (loss)	10,571	24,560
Investment Advisors [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	66,424	55,191
Expenses	34,577	31,625
Operating profit (loss)	31,847	23,566
Gain on sale of subsidiary	0	0
Total profit (loss)	31,847	23,566
Institutional Investors [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	68,657	63,162
Expenses	34,095	31,509
Operating profit (loss)	34,562	31,653
Gain on sale of subsidiary	0	0
Total profit (loss)	34,562	31,653
Investment Managers [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	61,008	53,820
Expenses	39,184	35,162
Operating profit (loss)	21,824	18,658
Gain on sale of subsidiary	0	0
Total profit (loss)	21,824	18,658
Investments In New Businesses [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	1,118	960
Expenses	4,249	3,738
Operating profit (loss)	-3,131	-2,778
Gain on sale of subsidiary	0	0
Total profit (loss)	($3,131)	($2,778)

Business_Segment_Information_R

Business Segment Information (Reconciliation Of Total Operating Profit Reported For Business Segments To Income From Operations In Consolidated Statements Of Operations) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Total operating profit from segments above	$90,091	$73,547
Noncontrolling interest reflected in segments	0	350
Income from operations	78,392	60,042
Operating Segments [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total operating profit from segments above	90,091	73,547
Corporate, Non-Segment [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Corporate overhead expenses	-11,699	-13,794
Segment Reconciling Items [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Noncontrolling interest reflected in segments	$0	$289

Business_Segment_Information_S1

Business Segment Information (Schedule Of Additional Information Pertaining To Business Segments) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Capital Expenditures	$17,035	$7,792
Depreciation	5,584	5,704
Amortization	9,214	8,242
Private Banks [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Capital Expenditures	8,798	4,851
Depreciation	3,732	3,933
Amortization	5,952	5,336
Investment Advisors [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Capital Expenditures	3,589	1,775
Depreciation	491	509
Amortization	2,197	1,957
Institutional Investors [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Capital Expenditures	1,288	363
Depreciation	209	230
Amortization	341	302
Investment Managers [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Capital Expenditures	2,135	623
Depreciation	512	462
Amortization	227	202
Investments In New Businesses [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Capital Expenditures	580	88
Depreciation	530	454
Amortization	440	388
Total From Business Segments [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Capital Expenditures	16,390	7,700
Depreciation	5,474	5,588
Amortization	9,157	8,185
Corporate Overhead [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Capital Expenditures	645	92
Depreciation	110	116
Amortization	$57	$57

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income Tax Contingency [Line Items]	'	'	'
Gross liability for unrecognized tax benefits, exclusive of interest and penalties	$12,683	'	$12,028
Unrecognized tax benefits that would affect effective tax rate	10,789	'	10,139
Interest and penalties on unrecognized benefits	825	'	754
Effective tax rates	35.90%	34.90%	'
Settlement and Lapse of Statute [Member]	'	'	'
Income Tax Contingency [Line Items]	'	'	'
Unrecognized tax benefits within the next twelve months	$4,196	'	'

Income_Taxes_Interest_And_Pena

Income Taxes (Interest And Penalties) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Income Tax Contingency [Line Items]	'	'
Gross liability for unrecognized tax benefits, exclusive of interest and penalties	$12,683	$12,028
Interest and penalties on unrecognized benefits	825	754
Gross uncertain tax positions	13,508	12,782
Amount included in Current liabilities	4,196	4,175
Amount included in Other long-term liabilities	$9,312	$8,607

Sale_of_SEI_Asset_Korea_Narrat

Sale of SEI Asset Korea (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 28, 2013
			SEI Asset Korea Co., Ltd. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'
Gain on sale of subsidiary	$5,582	$22,112	'
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
Net income	'	'	796
Less: Income attributable to the noncontrolling interests	'	'	350
Net income attributable to SEI AK	'	'	$446