Income Taxes - Schedule of Income Tax Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Current Federal	$ (19,476)us-gaap_CurrentFederalTaxExpenseBenefit	$ (7)us-gaap_CurrentFederalTaxExpenseBenefit	$ (7)us-gaap_CurrentFederalTaxExpenseBenefit
Current State	(1,496)	(108)
Total current	(20,972)us-gaap_CurrentIncomeTaxExpenseBenefit	(115)us-gaap_CurrentIncomeTaxExpenseBenefit	(7)us-gaap_CurrentIncomeTaxExpenseBenefit
Deferred Federal	36,917
Deferred State	313
Total deferred	37,230us-gaap_DeferredIncomeTaxExpenseBenefit
Total income tax benefit (expense)	$ 16,258us-gaap_IncomeTaxExpenseBenefit	$ (115)us-gaap_IncomeTaxExpenseBenefit	$ (7)us-gaap_IncomeTaxExpenseBenefit

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

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

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

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

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

Amount of deferred state and local tax expense (benefit) pertaining to income (loss) from continuing operations.