Income Taxes - Schedule of Reconciliation of Federal Statutory Rate to Company's Effective Tax Rate (Detail)		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal income tax provision at statutory rate		21.00%	35.00%	35.00%
State income taxes, net of federal income tax benefit		(15.90%)	(1.80%)	7.00%
Foreign income tax rate differential		(18.90%)	(58.00%)	24.40%
Tax effect of tax credits		1.30%	(20.10%)
Provision for (resolution of) tax matters		46.50%	27.80%	0.40%
Rate changes due to enacted legislation		7.20%	(1.30%)	1.90%
State benefit due to enacted legislation			(8.20%)
Effect of U.S. tax law change	[1]	(7.50%)	107.50%
Global Intangible Low-taxed Income		33.80%
Stock-based compensation		10.00%	(0.20%)	0.20%
Nondeductible officer's compensation		5.20%
Valuation allowance		15.70%	47.00%	(1.80%)
Other		7.80%	1.10%	(0.40%)
Actual tax rate		106.20%	128.80%	66.70%

[1] Due to the TCJA which was enacted in December 2017, provisional mandatory transition tax on accumulated foreign earnings was accrued as of December 31, 2017. Our U.S. deferred tax assets and liabilities as of December 31, 2017 were re-measured from 35% to 21%.