Income Taxes (Detail) - Components of Income Tax Benefit - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current income tax expense (benefit):
Federal	$ 18,524	$ 16,343	$ 4,744
State	2,326	(1,388)	10,504
Total	20,850	14,955	15,248
Deferred income tax expense:
Federal	12,048	7,901	31,572
State	4,849	8,314	1,895
Total	16,897	16,215	33,467
Total income tax expense	37,747	31,170	48,715
Income Tax Expense Benefit [Member]
Deferred income tax expense:
Total income tax expense	$ 37,747	$ 31,170	$ 48,715