Guarantor Financial Statements - Condensed Consolidating Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating revenue:
Oil production	$ 60,275	$ 107,507
Natural gas production	15,173	28,337
Natural gas liquids production	4,735	12,366
Other operational income	356	2,160
Derivative income, net	138	3,128
Total operating revenue	80,677	153,498
Operating expenses:
Lease operating expenses	19,547	27,577
Transportation, processing and gathering expenses	841	17,703
Production taxes	481	2,515
Depreciation, depletion and amortization	61,558	86,422
Write-down of oil and gas properties	129,204	491,412
Accretion expense	9,983	6,409
Salaries, general and administrative expenses	13,707	17,007
Incentive compensation expense	4,979	1,563
Other operational expenses	12,527	84
Total operating expenses	252,827	650,692
Loss from operations	(172,150)	(497,194)
Other (income) expenses:
Interest expense	15,241	10,365
Interest income	(114)	(122)
Other income	(298)	(143)
Other expense	2	0
Total other expenses	14,831	10,100
Loss before income taxes	(186,981)	(507,294)
Provision (benefit) for income taxes:
Current	(1,074)	0
Deferred	2,877	(179,906)
Total income taxes	1,803	(179,906)
Net loss	(188,784)	(327,388)
Comprehensive income (loss)	(187,995)	(339,891)
Parent
Operating revenue:
Oil production	61	4,350
Natural gas production	2,467	16,617
Natural gas liquids production	1,134	9,879
Other operational income	356	2,160
Derivative income, net	0	0
Total operating revenue	4,018	33,006
Operating expenses:
Lease operating expenses	2,728	4,976
Transportation, processing and gathering expenses	1,546	16,108
Production taxes	259	2,198
Depreciation, depletion and amortization	8,594	42,112
Write-down of oil and gas properties	9,324	491,412
Accretion expense	58	91
Salaries, general and administrative expenses	13,907	17,001
Incentive compensation expense	4,979	1,563
Other operational expenses	6,109	84
Total operating expenses	47,504	575,545
Loss from operations	(43,486)	(542,539)
Other (income) expenses:
Interest expense	15,241	10,344
Interest income	(114)	(101)
Other income	(39)	(133)
Other expense	2
Income from investment in subsidiaries	131,282	(29,027)
Total other expenses	146,372	(18,917)
Loss before income taxes	(189,858)	(523,622)
Provision (benefit) for income taxes:
Current	(1,074)
Deferred	0	(196,234)
Total income taxes	(1,074)	(196,234)
Net loss	(188,784)	(327,388)
Comprehensive income (loss)	(187,995)	(339,891)
Guarantor Subsidiaries
Operating revenue:
Oil production	60,214	103,157
Natural gas production	12,706	11,720
Natural gas liquids production	3,601	2,487
Other operational income	0	0
Derivative income, net	138	3,128
Total operating revenue	76,659	120,492
Operating expenses:
Lease operating expenses	16,806	22,601
Transportation, processing and gathering expenses	(705)	1,595
Production taxes	222	317
Depreciation, depletion and amortization	52,964	44,310
Write-down of oil and gas properties	119,531	0
Accretion expense	9,925	6,318
Salaries, general and administrative expenses	(200)	1
Other operational expenses	337	0
Total operating expenses	198,880	75,142
Loss from operations	(122,221)	45,350
Other (income) expenses:
Interest expense	0	21
Interest income	0	(16)
Other income	(259)	(10)
Other expense	0
Total other expenses	(259)	(5)
Loss before income taxes	(121,962)	45,355
Provision (benefit) for income taxes:
Current	0
Deferred	2,877	16,328
Total income taxes	2,877	16,328
Net loss	(124,839)	29,027
Comprehensive income (loss)	(124,839)	29,027
Non- Guarantor Subsidiaries
Operating expenses:
Lease operating expenses	13
Depreciation, depletion and amortization	0	0
Write-down of oil and gas properties	349	0
Accretion expense		0
Salaries, general and administrative expenses	0	5
Other operational expenses	6,081
Total operating expenses	6,443	5
Loss from operations	(6,443)	(5)
Other (income) expenses:
Interest income	0	(5)
Other income	0
Other expense	0
Income from investment in subsidiaries	6,443	0
Total other expenses	6,443	(5)
Loss before income taxes	(12,886)	0
Provision (benefit) for income taxes:
Current	0
Deferred	0	0
Total income taxes	0
Net loss	(12,886)	0
Comprehensive income (loss)	(12,886)	0
Eliminations
Operating expenses:
Depreciation, depletion and amortization	0	0
Write-down of oil and gas properties		0
Accretion expense		0
Other (income) expenses:
Income from investment in subsidiaries	(137,725)	29,027
Total other expenses	(137,725)	29,027
Loss before income taxes	137,725	(29,027)
Provision (benefit) for income taxes:
Current	0
Deferred	0	0
Total income taxes	0
Net loss	137,725	(29,027)
Comprehensive income (loss)	$ 137,725	$ (29,027)