Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Apr. 01, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Percentage of tax savings to be paid under tax receivable agreement		75.00%		75.00%			85.00%
Reduction in tax receivable agreement liability due to amendment	$ 67,200
Decrease in deferred income tax asset due to tax receivable agreement amendment	16,300
Increase in paid-in capital as a result of tax receivable agreement amendment	$ 51,000			$ 0	$ 50,318
Percentage of tax savings to be paid under tax receivable agreement to remaining EMDs and Ziffs		69.00%		69.00%
Estimated future payments under tax receivable agreement		$ 187,461		$ 187,461
Unfunded capital commitments of the Company to funds managed		86,100		86,100
Unfunded capital commitments by EMDs		60,200		60,200
Capital commitments by EMDs		14,900		14,900
Loss Contingencies [Line Items]
Legal provisions		116,900	$ 0	116,900	$ 0
Legal provisions		136,000		136,000			$ 19,100
Africo Litigation
Loss Contingencies [Line Items]
Legal provisions		116,900
Amounts claimants requesting		421,800		421,800
Value of mining rights submitted by DOJ		151,500		151,500
Legal provisions		$ 136,000		$ 136,000		$ 19,100