Condensed Consolidating Financial Information - (Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Revenues
Oil, natural gas liquids and natural gas	$ 47,852	$ 97,628
Other	308	397
Total revenues	48,160	98,025
Operatings expenses
Lease operating	17,379	24,355
Marketing, gathering, transportation and other	7,142	9,357
Production and ad valorem taxes	3,383	2,768
General and administrative	5,320	15,038
Depletion, depreciation and amortization	19,979	54,063
Accretion	545	474
Impairments	86,298	236,485
Other operating expenses	2,247	5,393
Total operating expenses	142,293	347,933
Other income (expenses)
Interest expense	(11,575)	(70,247)
Gain (loss) on derivative instruments		36,124
Total other income (expenses)	(11,575)	(34,123)
Reorganization items, net	(29,374)
Net loss before income taxes	(135,082)	(284,031)
Income tax expense	0	0
Net loss	(135,082)	(284,031)	$ (2,239,643)
Eliminations
Revenues
Other	(322)	(379)
Total revenues	(322)	(379)
Operatings expenses
Marketing, gathering, transportation and other	(322)	(379)
Total operating expenses	(322)	(379)
Other income (expenses)
Equity earnings (losses) in subsidiaries	57,185	240,364
Total other income (expenses)	57,185	240,364
Net loss before income taxes	57,185	240,364
Net loss	57,185	240,364
Parent Company Issuer | Reportable legal entity
Revenues
Oil, natural gas liquids and natural gas	16,912	29,283
Other	365	478
Total revenues	17,277	29,761
Operatings expenses
Lease operating	7,951	12,157
Marketing, gathering, transportation and other	3,105	3,492
Production and ad valorem taxes	1,041	472
General and administrative	1,822	5,208
Depletion, depreciation and amortization	7,222	12,334
Accretion	236	233
Impairments	30,622
Other operating expenses	2,226	5,409
Total operating expenses	54,225	39,305
Other income (expenses)
Interest expense	(11,575)	(70,247)
Gain (loss) on derivative instruments		36,124
Equity earnings (losses) in subsidiaries	(57,185)	(240,364)
Total other income (expenses)	(68,760)	(274,487)
Reorganization items, net	(29,374)
Net loss before income taxes	(135,082)	(284,031)
Net loss	(135,082)	(284,031)
Guarantor Subsidiaries | Reportable legal entity
Revenues
Oil, natural gas liquids and natural gas	30,940	68,345
Other	265	298
Total revenues	31,205	68,643
Operatings expenses
Lease operating	9,428	12,198
Marketing, gathering, transportation and other	4,359	6,244
Production and ad valorem taxes	2,342	2,296
General and administrative	3,498	9,830
Depletion, depreciation and amortization	12,757	41,729
Accretion	309	241
Impairments	55,676	236,485
Other operating expenses	21	(16)
Total operating expenses	88,390	309,007
Other income (expenses)
Net loss before income taxes	(57,185)	(240,364)
Net loss	$ (57,185)	$ (240,364)