Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenues	$ 45,244	$ 51,622	$ 146,701	$ 148,370
Asset-Based Fees
Disaggregation of Revenue [Line Items]
Revenues	21,039	26,016	70,979	77,088
Separately Managed Accounts
Disaggregation of Revenue [Line Items]
Revenues	21,039	26,016	70,979	77,088
Asset-Based Fees
Disaggregation of Revenue [Line Items]
Revenues	19,357	21,737	60,642	59,710
Impact of Fulcrum Fees
Disaggregation of Revenue [Line Items]
Revenues	(0)	(970)	(20)	(2,923)
Performance-Based Fees
Disaggregation of Revenue [Line Items]
Revenues	624	19	1,855	27
Sub-Advised Accounts
Disaggregation of Revenue [Line Items]
Revenues	19,981	20,786	62,477	56,814
Asset-Based Fees
Disaggregation of Revenue [Line Items]
Revenues	4,607	5,024	14,026	15,133
Expense Cap Reimbursements
Disaggregation of Revenue [Line Items]
Revenues	(389)	(204)	(835)	(665)
Performance-Based Fees
Disaggregation of Revenue [Line Items]
Revenues	6		54
Pzena Funds
Disaggregation of Revenue [Line Items]
Revenues	$ 4,224	$ 4,820	$ 13,245	$ 14,468