Long-Term Debt - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2015	Nov. 09, 2015	Jun. 30, 2015	Dec. 31, 2014
Revolving Credit Facility
Debt Disclosure [Line Items]
Borrowing base and revolving commitment	$ 395,000,000		$ 425,000,000
Letters of credit amount outstanding	1,800,000
Available borrowing capacity	$ 253,200,000
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	2.00%
Interest Rate at Period End, LIBOR component	0.25%
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 | Through March 31, 2016
Debt Disclosure [Line Items]
Covenant requirement - Debt to EBITDAX ratio	4.75
Revolving Credit Facility | Through June 30, 2016 (TTM)
Debt Disclosure [Line Items]
Covenant requirement - Debt to EBITDAX ratio	5.25
Revolving Credit Facility | Through December 31, 2016 (TTM)
Debt Disclosure [Line Items]
Covenant requirement - Debt to EBITDAX ratio	5.50
Revolving Credit Facility | Through March 31, 2017 (TTM)
Debt Disclosure [Line Items]
Covenant requirement - Debt to EBITDAX ratio	4.50
Covenant requirement - Senior Secured Debt to EBITDAX ratio	2.75
Revolving Credit Facility | Through maturity in September 2017 (TTM)
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
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 and revolving commitment		$ 275,000,000