Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Provisional income tax expense (benefit)		$ 103,700	$ 128,200
Transition tax		99,200	81,800
Provisional income tax benefit due to corporate rate reduction	$ 202,900	202,500	$ 210,000
Unrecognized deferred tax liability, undistributed earnings of foreign subsidiaries		1,500,000
GILTI tax expense (benefit)		$ 10,200
Income tax expense at federal statutory rate, rate		21.00%	35.00%	35.00%
Operating Loss Carryforwards [Line Items]
Valuation allowance		$ 90,366	$ 59,349
Increase (decrease) in the total valuation allowance		25,200
Net operating loss carryforwards for state income tax purposes		552,400
Federal operating loss carry forwards		68,900
Accrued interest and penalties related to the unrecognized tax benefits		1,500	1,300
Total unrecognized tax benefits		34,152	$ 31,558	$ 26,155	$ 21,834
Deferred Tax Asset, Net Operating Loss Carryforward
Operating Loss Carryforwards [Line Items]
Valuation allowance		$ 416,700