Fair Value Measurements (Narrative) (Details) (Fair Value Hierarchy, Level 3 [Member], USD $)	Mar. 31, 2013	Dec. 31, 2012
Fair Value Hierarchy, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment Reserve On Student Loans Held For Sale	$ 146,000
Impaired Student Loans At Fair Value	5,700,000
Auction Rate Securities Available For Sale	128,100,000
Financial Instruments, Owned, Principal Investments, at Fair Value	$ 68,103,000	$ 68,167,000

The fair value as of the balance sheet date of firm holdings in private equity, mezzanine, venture capital, merchant banking, real estate and special situations investments. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 320

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6475986&loc=d3e42546-110969

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