Investments of Operating Entities and Consolidated Funds - Operating Entities - Securities Sold, Not Yet Purchased (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	$ 974,867,000	$ 1,201,448,000
Common Stock
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	956,228,000	1,192,396,000
Corporate Bonds
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	1,349,000	37,000
Preferred Stock
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	17,278,000	9,009,000
Warrants and Rights
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	$ 12,000	$ 6,000