Long-Term Debt - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	May 07, 2015
Revolving Credit Facility
Debt Disclosure [Line Items]
Borrowing Base	$ 500,000,000
Maximum borrowing capacity	450,000,000
Optional additional borrowing	175,000,000
Letters of credit amount outstanding	1,800,000
Available borrowing capacity	286,200,000
Interest rate option two, base rate over federal funds effective rate	0.50%
Debt Instrument, Description of Variable Rate Basis	one-month Adjusted LIBOR
Interest rate option two, base rate over one-month Adjusted LIBOR	1.00%
Interest rate option two, applicable margin rate	1.75%
Commitment Fee Percentage at Period End	0.375%
Interest Rate at Period End	1.9375%
Interest Rate at Period End, LIBOR component	0.1875%
Revolving Credit Facility | Minimum
Debt Disclosure [Line Items]
Interest rate option one, applicable margin rate over Adjusted LIBOR	1.50%
Interest rate option two, applicable margin rate	0.50%
Commitment fees for undrawn credit facility	0.375%
Covenant requirement - Current ratio	1.0
Revolving Credit Facility | Maximum
Debt Disclosure [Line Items]
Interest rate option one, applicable margin rate over Adjusted LIBOR	2.50%
Interest rate option two, applicable margin rate	1.50%
Commitment fees for undrawn credit facility	0.50%
Revolving Credit Facility | Letter of Credit
Debt Disclosure [Line Items]
Maximum borrowing capacity	20,000,000
7.25% Senior Notes due 2019
Debt Disclosure [Line Items]
Senior Notes, Noncurrent	300,000,000	300,000,000
Annual interest rate	7.25%
7.25% Senior Notes due 2019 | Through March 31, 2016
Debt Disclosure [Line Items]
Redemption option, percent of principal	103.625%
7.25% Senior Notes due 2019 | Through December 31, 2016 (TTM)
Debt Disclosure [Line Items]
Redemption option, percent of principal	100.00%
8.50% Senior Notes due 2020
Debt Disclosure [Line Items]
Senior Notes, Noncurrent	775,000,000	775,000,000
Annual interest rate	8.50%
Subsequent Event | Revolving Credit Facility
Debt Disclosure [Line Items]
Borrowing Base			425,000,000
Maximum borrowing capacity			$ 425,000,000
Subsequent Event | Revolving Credit Facility | Through March 31, 2016 | Maximum
Debt Disclosure [Line Items]
Covenant requirement - Debt to EBITDAX ratio			4.75
Subsequent Event | Revolving Credit Facility | Through June 30, 2016 (TTM) | Maximum
Debt Disclosure [Line Items]
Covenant requirement - Debt to EBITDAX ratio			5.25
Subsequent Event | Revolving Credit Facility | Through December 31, 2016 (TTM) | Maximum
Debt Disclosure [Line Items]
Covenant requirement - Debt to EBITDAX ratio			5.50
Subsequent Event | Revolving Credit Facility | Through March 31, 2017 (TTM) | Maximum
Debt Disclosure [Line Items]
Covenant requirement - Debt to EBITDAX ratio			4.50
Covenant requirement - Senior Secured Debt to EBITDAX ratio			2.75
Subsequent Event | Revolving Credit Facility | Through maturity in September 2017 (TTM) | Maximum
Debt Disclosure [Line Items]
Covenant requirement - Debt to EBITDAX ratio			4.0
Debt to EBITDAX Ratio that precludes the payment of cash dividends on preferred stock			5.0