Income Taxes (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income (loss) before income taxes
U.S. operations			$ 70,484	$ 138,950	$ 154,947
Non-U.S. operations			42,680	40,641	60,982
Income before income taxes and non-controlling interest			113,164	179,591	215,929
Current provision
U.S. current provision			(9,991)	2,690	7,584
State and Local provision			65	38	108
Non-U.S. current provision			1,219	5,210	6,762
Deferred benefit
U.S. deferred provision (benefit)			106,415	13,547	3,345
State and Local provision (benefit)			(3,380)	194	48
Non-US deferred provision (benefit)			(62)	(428)	592
Provision (benefit) for income taxes			94,266	$ 21,251	$ 18,439
Reconciliation of tax provision
Provisional deferred tax expense			90,600
Gain from tax receivable agreement			$ 86,600
Tax provision at the U.S. federal statutory rate (as a percent)			35.00%	35.00%	35.00%
Less: rate attributable to noncontrolling interest			(19.10%)	(24.40%)	(27.80%)
State, local and foreign taxes, net of federal benefit (as a percent)			(1.90%)	1.30%	1.40%
Impact of 2017 Tax Act on deferred tax assets			80.10%
Impact of 2017 Tax Act on tax receivable agreement obligation			(12.90%)
Non-deductible expenses, net			1.90%
Other, net			0.20%
Provision for income taxes (as a percent)			83.30%	11.90%	8.60%
Deferred income tax assets
Tax Receivable Agreement			$ 101,594	$ 185,677
Share-based compensation			5,213	5,664
Intangibles			14,547
Fixed assets and other			13,425	2,518
Tax credits and net operating loss carryforwards			50,867
Less: Valuation allowance on net operating loss carryforwards and tax credits			(43,544)
Total deferred income tax assets			142,102	193,859
Deferred income tax liabilities
Intangibles			16,342
Fixed assets				84
Total deferred income tax liabilities			16,342	84
Unrecognized tax benefits			$ 7,300	$ 0
Forecast
Reconciliation of tax provision
Tax provision at the U.S. federal statutory rate (as a percent)	21.00%	21.00%