Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Percentage of tax savings to be paid under tax receivable agreement		75.00%	85.00%
Reduction in tax receivable agreement liability due to amendment		$ 67,200		$ 18,000	$ 72,600
Decrease in deferred income tax asset due to tax receivable agreement amendment		16,300		7,500	33,400
Increase in paid-in capital as a result of tax receivable agreement amendment		$ 50,967	$ 0	10,520	$ 39,200
Percentage of tax savings to be paid under tax receivable agreement to remaining EMDs and Ziffs		69.00%
Estimated future payments under tax receivable agreement		$ 205,752
Unfunded capital commitments of the Company to funds managed		55,800
Capital commitments by EMDs		49,600
Loss Contingencies [Line Items]
Legal settlements and provisions		19,100	$ 31,750	$ 0
Africo Litigation
Loss Contingencies [Line Items]
Legal settlements and provisions		19,100
Amounts claimants requesting		290,400
Value of mining rights submitted by DOJ		$ 188,700
A Commercial Matter
Loss Contingencies [Line Items]
Legal settlements and provisions	$ 3,000