Related-Party Transactions - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
	Jan. 31, 2020	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Related Party Transaction [Line Items]
Revenues		$ 102,877	$ 84,583	$ 84,431	$ 69,744	$ 76,932	$ 68,138	$ 64,292	$ 64,686	$ 341,635	$ 274,048	$ 252,179
Fees receivable		29,202				30,384				29,202	30,384
Payable to related parties pursuant to tax receivable agreement		194,764				98,956				194,764	98,956
Investee shares received upon note receivable conversion (in shares)	2,278,524
Notes receivable	$ 902
Asset acquisition. consideration transferred	6,373
Payments for asset acquisitions	4,000
Asset acquisition, contingent consideration, liability		1,000								1,000
Asset acquisition, equity shares contributed by investee, value	2,201
Asset acquisition, direct transaction fees	$ 172
Amortization period of intangible assets acquired	7 years
General Partnerships
Related Party Transaction [Line Items]
Fees receivable		14,814				16,970				14,814	16,970
Joint Venture
Related Party Transaction [Line Items]
Payable to related parties pursuant to tax receivable agreement		325				$ 428				325	428
Service Agreement Fees Paid | Joint Venture
Related Party Transaction [Line Items]
Amount payable to joint venture										3,978	5,289	5,058
Management and advisory fees
Related Party Transaction [Line Items]
Revenues										289,444	244,920	217,773
Management and advisory fees | General Partnerships
Related Party Transaction [Line Items]
Revenues		199,422									161,323	134,343
Incentive fees
Related Party Transaction [Line Items]
Revenues										$ 52,191	29,128	34,406
Incentive fees | General Partnerships
Related Party Transaction [Line Items]
Revenues		$ 47,962									$ 24,077	$ 31,876