Income Taxes - (Benefit) Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
U.S. Federal	$ 21,171	$ 17,203	$ 7,976
State	2,976	2,049	1,851
Foreign	2,016	1,683	1,645
Current income tax expense (benefit)	26,163	20,935	11,472
Deferred:
U.S. Federal	(103,518)	4,005	13,201
State	6,948	3,039	1,538
Foreign	(61)	701	(304)
Deferred income tax expense (benefit)	(96,631)	7,745	14,435
Total	$ (70,468)	$ 28,680	$ 25,907