Income Taxes - Summary of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ (3,933)	$ 14,918	$ 34,768
State	34	2,666	5,856
Foreign	81	96	68
Total current taxes	(3,818)	17,680	40,692
Deferred:
Federal	(4,144)	182	(275)
State	(757)	(9)	(46)
Foreign	(12)	(18)	(40)
Total deferred taxes	(4,913)	155	(361)
Income tax (benefit) expense	$ (8,731)	$ 17,835	$ 40,331