Income Taxes - Components of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Federal - Current	$ (9)	$ 134	$ 475
State - Current	0	0	0
Total current income tax expense	(9)	134	475
Federal - Deferred	(11,667)	273,576	122,853
State - Deferred	(4,447)	33,881	11,730
Total deferred income tax expense	(16,114)	307,457	134,583
Total income tax expense (benefit)	$ (16,123)	$ 307,591	$ 135,058

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

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