Income Taxes - Income Tax Provision (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current income tax provision:
Federal	$ 25,105	$ 18,722	$ 1,745
State	2,560	3,131	404
Total	27,665	21,853	2,149
Deferred income tax provision (benefit):
Federal	987	3,118	(11,182)
State	37	456	(1,516)
Total	1,024	3,574	(12,698)
Total income tax provision (benefit)	$ 28,689	$ 25,427	$ (10,549)