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

The cash inflow associated with the aggregate amount received by the company through the sale of marketable securities (trading, held-to-maturity, or available-for-sale) during the period. Excludes principal prepayments and maturities of marketable securities.

No definition available.