Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Investment advisory fees	$ 33,948	$ 37,065	$ 98,758	$ 112,318
Loan write-off period			7 years
Net of Expense Reimbursement | VIEs That are Not Consolidated
Related Party Transaction [Line Items]
Investment advisory fees	100	300	$ 400	900
Employees
Related Party Transaction [Line Items]
Loans to employees	2,200		2,200		$ 1,700
Pzena Mutual Funds
Related Party Transaction [Line Items]
Investment advisory fees waived	200	300	800	800
Company's Executive Officers and Other Employees
Related Party Transaction [Line Items]
Investment advisory fees waived	$ 200	$ 200	$ 600	$ 500