Income Taxes - Schedule of Domestic and Foreign Components of Pretax Income (Loss) from Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
United States	$ (40,920)	$ (63,315)	$ 2,382
Foreign	80,255	74,121	76,194
Income before income taxes	$ 39,335	$ 10,806	$ 78,576