Income Taxes - Schedule of Income Before Income Taxes (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Domestic	$ (84,278,000)	$ 33,543,000	$ 107,158,000
Foreign	18,634,000	82,325,000	142,613,000
Income (loss) before taxes	$ (65,644,000)	$ 115,868,000	$ 249,771,000