Investments of Operating Entities and Consolidated Funds - Other Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2019		Dec. 31, 2018
Investment Holdings [Line Items]
Other investments	$ 204,168		$ 181,407
Portfolio Funds, Consolidated Funds	171,186		186,395
Portfolio Funds
Investment Holdings [Line Items]
Other investments	131,740	[1]	123,241	[2]
Carried interest [Member]
Investment Holdings [Line Items]
Other investments	25,186	[1]	17,995	[2]
Equity Method Investments
Investment Holdings [Line Items]
Other investments	47,242		40,171
Enterprise LP [Member]
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	96,308		97,656
Merger Fund [Member]
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	$ 74,878		$ 88,739

[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 and carried interest in portfolio funds 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 condensed 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 and carried interest in portfolio funds 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 condensed consolidated statement of financial condition.