Income Taxes - Reconciliation of Income Tax Provision (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax at U.S. federal statutory tax rate		$ 18,044	$ 11,953	$ 28,457
State income taxes, net of federal tax benefit		1,520	(31)	594
Foreign rate differential		(5,119)	(4,620)	(14,736)
Tax holidays		(3,080)	(4,050)	(2,951)
Permanent differences		13,257	12,150	8,749
Tax credits		(8,218)	(8,979)	(5,102)
Foreign withholding and other taxes		2,834	(840)	2,661
Valuation allowance		781	1,549	(1,689)
Uncertain tax positions		402	771	(1,812)
Statutory tax rate changes		475	96	2,536
Change in assertion related to foreign earnings distribution	$ 1,000	952
2017 Tax Reform Act			(217)	32,705
Other		(6)	209	(321)
Total provision for income taxes		$ 21,842	$ 7,991	$ 49,091