Income Taxes - Schedule of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
Federal	$ 40,607	$ 22,109	$ 26,240
State	500	1,063	1,218
Foreign	22,344	22,067	16,458
Deferred
Federal	17,594	1,828	6,410
State	419	904	281
Foreign	(6,937)	6,350	(9,389)
Income tax provision	$ 74,527	$ 54,321	$ 41,218