CONSOLIDATED STATEMENT OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating revenue:
Oil production									$ 281,246	$ 416,497	$ 516,104
Natural gas production									64,601	83,509	166,494
Natural gas liquids production									28,888	32,322	85,642
Other operational income									2,657	4,369	7,951
Derivative income, net									0	7,952	19,351
Total operating revenue	$ 113,107	$ 94,427	$ 89,319	$ 80,677	$ 110,499	$ 132,196	$ 149,525	$ 153,498	377,392	544,649	795,542
Operating expenses:
Lease operating expenses									79,650	100,139	176,495
Transportation, processing and gathering expenses									27,760	58,847	64,951
Production taxes									3,148	6,877	12,151
Depreciation, depletion and amortization									220,079	281,688	340,006
Write-down of oil and gas properties	73,094	36,484	118,649	129,204	351,062	295,679	224,294	491,412	357,431	1,362,447	351,192
Accretion expense									40,229	25,988	28,411
Salaries, general and administrative expenses									58,928	69,384	66,451
Incentive compensation expense									13,475	2,242	10,361
Restructuring fees	13,424	5,784	9,436	953					29,597	0	0
Other operational expenses	6,187	9,059	27,680	12,527					55,453	2,360	862
Derivative expense, net									810	0	0
Total operating expenses									886,560	1,909,972	1,050,880
Loss from operations	(90,234)	(72,128)	(174,656)	(172,150)	(342,759)	(297,209)	(228,161)	(497,194)	(509,168)	(1,365,323)	(255,338)
Other (income) expenses:
Interest expense									64,458	43,928	38,855
Interest income									(550)	(580)	(574)
Other income									(1,439)	(1,783)	(2,332)
Other expense									596	434	274
Reorganization items	10,947	0	0	0					10,947	0	0
Total other expenses									74,012	41,999	36,223
Loss before income taxes									(583,180)	(1,407,322)	(291,561)
Provision (benefit) for income taxes:
Current									(5,674)	(44,096)	159
Deferred									13,080	(272,311)	(102,177)
Total income taxes									7,406	(316,407)	(102,018)
Net loss	$ (116,406)	$ (89,635)	$ (195,761)	$ (188,784)	$ (318,656)	$ (291,965)	$ (152,906)	$ (327,388)	$ (590,586)	$ (1,090,915)	$ (189,543)
Basic loss per share (in usd per share)	$ (20.76)	$ (16.01)	$ (35.05)	$ (33.89)	$ (57.63)	$ (52.82)	$ (27.68)	$ (59.33)	$ (105.63)	$ (197.45)	$ (35.95)
Diluted loss per share (in usd per share)	$ (20.76)	$ (16.01)	$ (35.05)	$ (33.89)	$ (57.63)	$ (52.82)	$ (27.68)	$ (59.33)	$ (105.63)	$ (197.45)	$ (35.95)
Average shares outstanding (in shares)									5,591	5,525	5,272
Average shares outstanding assuming dilution (in shares)									5,591	5,525	5,272