Income Taxes - Reconciliation of Provision for Income Taxes at US Federal Statutory Rate to Provision in Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Provision (benefit) at U.S. federal statutory rate		$ 41,008	$ (33,240)	$ (87,592)
U.S. valuation allowance		17,676	19,141	64,907
Foreign earnings taxed at different rates, including foreign losses without benefit		6,203	51,612	103,231
U.S. Tax Act	$ 3,700	0	0	3,709
State and local taxes, net of U.S. federal (expense) benefit		(1,056)	2,438	(2,028)
Adjustments to previously accrued taxes		(5,354)	(14,160)	(6,621)
Change in indefinite reinvestment assertion		0	(2,700)	14,566
Other		(536)	3,813	12,782
Provision for income taxes		$ 68,649	$ 55,224	116,196
Tax credit expirations				$ 8,100