Compensation - Compensation Expense Related to Class A Common Stock (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LPU amortization	$ 18,455	$ 4,213	$ 54,288	$ 17,947
RSU amortization	2,785	1,599	7,640	5,309
Equity-based compensation and allocations of net income to limited partnership units and FPUs	33,007	40,330	103,030	96,223
LPUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock and grants of exchangeability	3,554	24,245	28,950	53,368
Class A Common Stock [Member] | LPUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock and grants of exchangeability	3,554	24,245	28,950	53,368
Allocations of net income	8,213	10,273	12,152	19,599
LPU amortization	18,455	4,213	54,288	17,947
RSU amortization	2,785	1,599	7,640	5,309
Equity-based compensation and allocations of net income to limited partnership units and FPUs	$ 33,007	$ 40,330	$ 103,030	$ 96,223