Income Taxes - Components of Income Tax Expense (Benefit) Attributable to Current Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income before income tax expense	$ 26,298	$ 27,327	$ 45,339
Current:
Federal tax	432	753	575
State tax	622	1,087	958
Foreign tax	16	2	0
Current income tax benefit	1,070	1,842	1,533
Deferred:
Federal tax	(55,716)	6,046	16,790
State tax	(2,969)	(1,249)	(355)
Foreign tax	(322)	(57)	(159)
Deferred income tax benefit	(59,007)	4,740	16,276
Total income tax (benefit) / expense	$ (57,937)	$ 6,582	$ 17,809