Income Taxes - Additional information (Detail)	12 Months Ended
	Dec. 31, 2016 USD ($) Agreement shares	Dec. 31, 2015 USD ($) shares
Tax Credit Carryforward [Line Items]
Effective income tax rate	39.50%	39.40%
Effective income tax rate reconciliation noncontrolling interest	2.00%	2.50%
Undistributed earnings of foreign operations	$ 0	$ 0
Unrecognized tax benefits, Current period tax positions	2,773,000
Unrecognized tax benefits including interest	465,000
Unrecognized tax benefits related with acquisition	2,773,000
Unrecognized tax benefits, Income tax penalties and interest expense	465,000
Total liability related to uncertain tax positions	2,608,000	300,000
Portion of unrecognized tax benefit, if recognized would reduce income tax expense	2,608,000
Decrease in next twelve months for unrecognized tax benefits	$ 2,608,000
Number of tax receivable agreements | Agreement	2
Applicable tax savings	85.00%
Percentage of remaining tax savings	15.00%
Income tax rate maximum tax liability	3.50%
Other income (expense) reflecting change in tax benefit obligation	$ (72,000)	2,549,000
Deferred tax asset	413,581,000	118,646,000
Deferred tax liability	4,412,000	1,288,000
Tax benefit obligation	419,071,000	140,191,000
Continuing LLC Owners [Member]
Tax Credit Carryforward [Line Items]
Decrease in deferred tax assets	(25,046,000)	(35,661,000)
Deferred tax asset	332,471,000	154,335,000
Deferred tax liability	$ 285,730,000	$ 136,950,000
Class A Common Stock [Member] | Continuing LLC Owners [Member]
Tax Credit Carryforward [Line Items]
Number of shares exchanged | shares	24,704,610	10,491,055
Canada [Member]
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	$ 82,000
Operating loss carryforwards, expiration date	2034
Valuation allowance recorded	$ 0