Subsequent Events	6 Months Ended
Jun. 30, 2012
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events 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 interests in SEI Asset Korea Co., Ltd. (SEI AK). SEI AK is located in South Korea and provides domestic equity and fixed income investment management services to financial institutions and pension funds. Consummation of the acquisition of SEI AK under the definitive agreement is subject to regulatory approvals and other customary closing conditions. The Company's ownership interest in SEI AK is 56.1 percent as of July 31, 2012. The Company consolidates the assets, liabilities and operations of SEI AK in its Consolidated Financial Statements. The ownership interests in SEI AK for MetLife and IFC is reflected in Noncontrolling interest in the Consolidated Financial Statements. Upon closing of the agreement, the then current cash balance of SEI AK will be distributed to the Company, Metlife and IFC in accordance with the ownership interests. As of June 30, 2012, SEI AK has total corporate assets of $48,776, of which $42,553 is included in Cash and Cash equivalents on the Consolidated Balance Sheets. All other accounts of SEI AK are not material to any financial statement line item in the Consolidated Financial Statements. The Company did not provide U.S. deferred taxes on the undistributed earnings of SEI AK since its inception because those earnings were considered to be indefinitely reinvested. As a result of the potential sale of SEI AK, the Company no longer considers undistributed earnings to be indefinitely reinvested and, therefore, must accrue approximately $5,000 for U.S. deferred taxes during the three months ended September 30, 2012 on the cumulative undistributed earnings of SEI AK. If the requisite regulatory approvals are obtained, the other conditions to closing are satisfied or waived and the transaction is consummated, then the Company expects to recognize a net after tax gain on the sale of its shares of SEI AK depending upon revenue during a pre-closing measurement period and specified revenues during three one-year periods after the closing.

Subsequent Events

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 interests in SEI Asset Korea Co., Ltd. (SEI AK). SEI AK is located in South Korea and provides domestic equity and fixed income investment management services to financial institutions and pension funds. Consummation of the acquisition of SEI AK under the definitive agreement is subject to regulatory approvals and other customary closing conditions.

The Company's ownership interest in SEI AK is 56.1 percent as of July 31, 2012. The Company consolidates the assets, liabilities and operations of SEI AK in its Consolidated Financial Statements. The ownership interests in SEI AK for MetLife and IFC is reflected in Noncontrolling interest in the Consolidated Financial Statements. Upon closing of the agreement, the then current cash balance of SEI AK will be distributed to the Company, Metlife and IFC in accordance with the ownership interests.

As of June 30, 2012, SEI AK has total corporate assets of $48,776, of which $42,553 is included in Cash and Cash equivalents on the Consolidated Balance Sheets. All other accounts of SEI AK are not material to any financial statement line item in the Consolidated Financial Statements.

The Company did not provide U.S. deferred taxes on the undistributed earnings of SEI AK since its inception because those earnings were considered to be indefinitely reinvested. As a result of the potential sale of SEI AK, the Company no longer considers undistributed earnings to be indefinitely reinvested and, therefore, must accrue approximately $5,000 for U.S. deferred taxes during the three months ended September 30, 2012 on the cumulative undistributed earnings of SEI AK.

If the requisite regulatory approvals are obtained, the other conditions to closing are satisfied or waived and the transaction is consummated, then the Company expects to recognize a net after tax gain on the sale of its shares of SEI AK depending upon revenue during a pre-closing measurement period and specified revenues during three one-year periods after the closing.