Investments of Operating Entities and Consolidated Funds - Other Investments - Quarterly (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014
Investment Holdings [Line Items]
Other Investments, Consolidated Funds	$ 263,818		$ 189,377
Other investments	140,647		167,464
Portfolio Funds, at fair value
Investment Holdings [Line Items]
Other Investments, Consolidated Funds	263,818	[1]	188,884	[2]
Other investments	111,360	[1]	103,466	[2]
Real Estate Equity Investment
Investment Holdings [Line Items]
Other investments	1,921		2,175
Equity Method Investments
Investment Holdings [Line Items]
Other investments	27,067		61,443
Lehman claims, at fair value
Investment Holdings [Line Items]
Other Investments, Consolidated Funds	0		493
Other investments	299		$ 380
Hollenfels
Investment Holdings [Line Items]
Business Combination, Consideration Transferred	$ 469,800

[1] In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated statement of financial condition.

[2] In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated statement of financial condition.