Income Taxes - Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Beginning valuation allowance	$ 137,976	$ 140,117
Increase (decrease) as reflected in income tax expense	12,453	(114)
Cumulative translation adjustment	10,412	(2,027)
Ending valuation allowance	$ 160,841	$ 137,976