Guarantor Financial Statements - Condensed Consolidating Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating revenue:
Oil production	$ 72,711	$ 111,585	$ 132,986	$ 219,092
Natural gas production	12,553	26,907	27,726	55,244
Natural gas liquids production	3,718	11,033	8,453	23,399
Other operational income	337	0	693	1,792
Derivative income, net	0	0	0	2,427
Total operating revenue	89,319	149,525	169,858	301,954
Operating expenses:
Lease operating expenses	18,826	27,429	38,373	55,006
Transportation, processing and gathering expenses	7,183	19,940	8,024	37,643
Production taxes	578	1,827	1,059	4,342
Depreciation, depletion and amortization	46,231	77,951	107,789	164,373
Write-down of oil and gas properties	118,649	224,294	247,853	715,706
Accretion expense	10,082	6,408	20,065	12,817
Salaries, general and administrative expenses	20,014	16,418	32,768	33,425
Incentive compensation expense	4,670	1,264	9,649	2,827
Restructuring fees	9,436	0	10,389	0
Other operational expenses	27,680	1,454	40,207	1,170
Derivative expense, net	626	701	488	0
Total operating expenses	263,975	377,686	516,664	1,027,309
Loss from operations	(174,656)	(228,161)	(346,806)	(725,355)
Other (income) expenses:
Interest expense	17,599	10,472	32,840	20,837
Interest income	(302)	(66)	(416)	(188)
Other income	(270)	(613)	(568)	(756)
Other expense	9	0	11	0
Total other expenses	17,036	9,793	31,867	19,893
Loss before income taxes	(191,692)	(237,954)	(378,673)	(745,248)
Provision (benefit) for income taxes:
Current	(2,113)	0	(3,187)	0
Deferred	6,182	(85,048)	9,059	(264,954)
Total income taxes	4,069	(85,048)	5,872	(264,954)
Net loss	(195,761)	(152,906)	(384,545)	(480,294)
Comprehensive income (loss)	(207,117)	(183,062)	(395,112)	(522,953)
Parent
Operating revenue:
Oil production	1,323	6,504	1,384	10,854
Natural gas production	3,959	15,647	6,426	32,264
Natural gas liquids production	2,375	8,077	3,509	17,956
Other operational income	337		693	1,792
Derivative income, net				0
Total operating revenue	7,994	30,228	12,012	62,866
Operating expenses:
Lease operating expenses	3,814	5,111	6,542	10,087
Transportation, processing and gathering expenses	6,021	17,974	7,567	34,082
Production taxes	383	1,436	642	3,634
Depreciation, depletion and amortization	10,470	44,052	19,064	86,164
Write-down of oil and gas properties	6,534	179,125	15,858	670,537
Accretion expense	58	91	116	182
Salaries, general and administrative expenses	20,013	16,398	32,967	33,399
Incentive compensation expense	4,670	1,264	9,649	2,827
Restructuring fees	9,436		10,389
Other operational expenses	27,736	1,454	33,845	1,170
Derivative expense, net	0
Total operating expenses	89,135	266,905	136,639	842,082
Loss from operations	(81,141)	(236,677)	(124,627)	(779,216)
Other (income) expenses:
Interest expense	17,599	10,472	32,840	20,816
Interest income	(302)	(46)	(416)	(147)
Other income	(20)	(187)	(59)	(320)
Other expense	9		11
(Income) loss from investment in subsidiaries	99,447	(16,147)	230,729	(45,174)
Total other expenses	116,733	(5,908)	263,105	(24,825)
Loss before income taxes	(197,874)	(230,769)	(387,732)	(754,391)
Provision (benefit) for income taxes:
Current	(2,113)		(3,187)
Deferred	0	(77,863)	0	(274,097)
Total income taxes	(2,113)	(77,863)	(3,187)	(274,097)
Net loss	(195,761)	(152,906)	(384,545)	(480,294)
Comprehensive income (loss)	(207,117)	(183,062)	(395,112)	(522,953)
Guarantor Subsidiaries
Operating revenue:
Oil production	71,388	105,081	131,602	208,238
Natural gas production	8,594	11,260	21,300	22,980
Natural gas liquids production	1,343	2,956	4,944	5,443
Other operational income	0		0	0
Derivative income, net				2,427
Total operating revenue	81,325	119,297	157,846	239,088
Operating expenses:
Lease operating expenses	15,012	22,318	31,818	44,919
Transportation, processing and gathering expenses	1,162	1,966	457	3,561
Production taxes	195	391	417	708
Depreciation, depletion and amortization	35,761	33,899	88,725	78,209
Write-down of oil and gas properties	112,114	0	231,645	0
Accretion expense	10,024	6,317	19,949	12,635
Salaries, general and administrative expenses	1	0	(199)	1
Restructuring fees			0
Other operational expenses	(57)	0	280	0
Derivative expense, net	626	701	488
Total operating expenses	174,838	65,592	373,580	140,033
Loss from operations	(93,513)	53,705	(215,734)	99,055
Other (income) expenses:
Interest expense	0	0	0	21
Interest income	0	(19)	0	(35)
Other income	(250)	(423)	(509)	(433)
Other expense	0
Total other expenses	(250)	(442)	(509)	(447)
Loss before income taxes	(93,263)	54,147	(215,225)	99,502
Provision (benefit) for income taxes:
Current	0		0
Deferred	6,182	9,082	9,059	25,410
Total income taxes	6,182	9,082	9,059	25,410
Net loss	(99,445)	45,065	(224,284)	74,092
Comprehensive income (loss)	(99,445)	45,065	(224,284)	74,092
Non- Guarantor Subsidiaries
Operating expenses:
Lease operating expenses	0		13
Depreciation, depletion and amortization			0	0
Write-down of oil and gas properties	1	45,169	350	45,169
Accretion expense				0
Salaries, general and administrative expenses	0	20	0	25
Restructuring fees			0
Other operational expenses	1		6,082
Derivative expense, net	0
Total operating expenses	2	45,189	6,445	45,194
Loss from operations	(2)	(45,189)	(6,445)	(45,194)
Other (income) expenses:
Interest income	0	(1)	0	(6)
Other income	0	(3)	0	(3)
Other expense	0
(Income) loss from investment in subsidiaries	1	28,918	6,444	28,918
Total other expenses	1	28,914	6,444	28,909
Loss before income taxes	(3)	(74,103)	(12,889)	(74,103)
Provision (benefit) for income taxes:
Current	0		0
Deferred	0	(16,267)	0	(16,267)
Total income taxes	0	(16,267)	0	(16,267)
Net loss	(3)	(57,836)	(12,889)	(57,836)
Comprehensive income (loss)	(3)	(57,836)	(12,889)	(57,836)
Eliminations
Operating expenses:
Depreciation, depletion and amortization			0	0
Write-down of oil and gas properties				0
Accretion expense				0
Other (income) expenses:
(Income) loss from investment in subsidiaries	(99,448)	(12,771)	(237,173)	16,256
Total other expenses	(99,448)	(12,771)	(237,173)	16,256
Loss before income taxes	99,448	12,771	237,173	(16,256)
Provision (benefit) for income taxes:
Current	0		0
Deferred	0		0	0
Total income taxes	0		0
Net loss	99,448	12,771	237,173	(16,256)
Comprehensive income (loss)	$ 99,448	$ 12,771	$ 237,173	$ (16,256)