Income Taxes - Additional Information (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 income tax benefit	$ 159	$ (10,904)	$ 15,022
Current income tax receivable	7,212	7,366
Operating loss carryforwards	281,240
Operating loss carryforwards begins to expire	2033
Operating loss carryforwards expiration year	2034
Statutory depletion deductions available for tax reporting purposes	920
Income taxes allocated to other comprehensive income related to oil and gas hedges	49,601	(17,003)	3,918
Unrecognized tax benefits, interest expense	$ 0	$ 0