Investments of Operating Entities and Consolidated Funds - Operating Entities - Variable Interest Entities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Assets	$ 7,828,199	$ 5,162,025
Liabilities	6,659,078	3,866,575
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	8,000,000	6,100,000
Liabilities	1,300,000	617,500
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure	210,700	241,200
Maximum exposure regarding nonconsolidated variable interest entities	$ 326,000	$ 261,700