Investments Of Operating Entities And Consolidated Funds - Consolidated Funds - Other Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	$ 192,670	$ 175,769
Enterprise LP [Member]
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	104,475	99,153
Merger Fund
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	0	76,616
Cowen Sustainable Investments I LP
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	$ 88,195	$ 0