Income Taxes - Additional information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) agreement shares	Mar. 31, 2018	Dec. 31, 2018 USD ($)
Tax Credit Carryforward [Line Items]
Effective income tax rate	14.30%	22.70%
Net deferred tax assets	$ 430,149		$ 412,538
Total liability related to uncertain tax positions	$ 370		300
Number of tax receivable agreements | agreement	2
Applicable tax savings	85.00%
Percentage of remaining tax savings	15.00%
Tax benefit obligation	$ 449,490		$ 429,233
TRA Holders
Tax Credit Carryforward [Line Items]
Decrease in deferred tax assets	666
Deferred tax asset	19,766
Deferred tax liability	$ 16,904
Class A Common Stock
Tax Credit Carryforward [Line Items]
Number of shares exchanged | shares	858,810
Class A Common Stock | TRA Holders
Tax Credit Carryforward [Line Items]
Number of shares exchanged | shares	858,810