Revenue - Disaggregation of Revenue By Product (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 38,145	$ 15,381	$ 104,901	$ 42,682
Management and Advisory Fees
Disaggregation of Revenue [Line Items]
Total revenues	37,939	15,222	104,029	41,821
Subscriptions
Disaggregation of Revenue [Line Items]
Total revenues	153	156	486	496
Consulting Agreements and Referral Fees
Disaggregation of Revenue [Line Items]
Total revenues	0	0	150	55
Other Revenue
Disaggregation of Revenue [Line Items]
Total revenues	$ 53	$ 3	$ 236	$ 310