Income Taxes - Components of (Loss) Income Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S	$ (49,761)	$ (2,225)	$ (6,861)
Non-U.S	13,350	15,927	18,610
(Loss) income before income taxes	$ (36,411)	$ 13,702	$ 11,749