Guarantor Financial Statements - Condensed Consolidating Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating revenue:
Oil production									$ 416,497	$ 516,104	$ 715,104
Natural gas production									83,509	166,494	190,580
Natural gas liquids production									32,322	85,642	60,687
Other operational income									4,369	7,951	7,808
Derivative income, net									7,952	19,351	0
Total operating revenue	$ 110,499	$ 132,196	$ 149,525	$ 153,498	$ 184,780	$ 183,213	$ 207,046	$ 223,830	544,649	795,542	974,179
Operating expenses:
Lease operating expenses									100,139	176,495	201,153
Transportation, processing and gathering expenses									58,847	64,951	42,172
Production taxes									6,877	12,151	15,029
Depreciation, depletion, amortization									281,688	340,006	350,574
Write-down of oil and gas properties	351,062	295,679	224,294	491,412	304,062	47,130	0	0	1,362,447	351,192	0
Accretion expense									25,988	28,411	33,575
Salaries, general and administrative expenses									69,384	66,451	59,524
Franchise tax settlement									0	0	12,590
Incentive compensation expense									2,242	10,361	15,340
Other operational expenses									2,360	862	151
Derivative expense, net									0	0	2,090
Total operating expenses									1,909,972	1,050,880	732,198
Income (loss) from operations	(342,759)	(297,209)	(228,161)	(497,194)	(286,147)	(34,356)	16,613	48,552	(1,365,323)	(255,338)	241,981
Other (income) expenses:
Interest expense									43,928	38,855	32,837
Interest income									(580)	(574)	(1,695)
Other income									(1,783)	(2,332)	(2,799)
Other expense									434	274	0
Loss on early extinguishment of debt									0	0	27,279
Loss from investment in subsidiaries									0	0	0
Total other expenses									41,999	36,223	55,622
Income (loss) before income taxes									(1,407,322)	(291,561)	186,359
Provision (benefit) for income taxes:
Current									(44,096)	159	(10,904)
Deferred									(272,311)	(102,177)	79,629
Total income taxes									(316,407)	(102,018)	68,725
Net income (loss)	$ (318,656)	$ (291,965)	$ (152,906)	$ (327,388)	$ (190,515)	$ (29,415)	$ 4,444	$ 25,943	(1,090,915)	(189,543)	117,634
Comprehensive income (loss)									(1,156,278)	(104,166)	86,739
Parent [Member]
Operating revenue:
Oil production									12,804	29,701	30,475
Natural gas production									41,646	86,812	68,895
Natural gas liquids production									22,375	61,200	32,293
Other operational income									4,369	7,551	7,163
Derivative income, net									0	0
Total operating revenue									81,194	185,264	138,826
Operating expenses:
Lease operating expenses									16,264	18,719	14,680
Transportation, processing and gathering expenses									50,247	53,028	28,322
Production taxes									5,631	8,324	6,229
Depreciation, depletion, amortization									123,724	138,313	93,579
Write-down of oil and gas properties									785,463	351,192
Accretion expense									365	230	372
Salaries, general and administrative expenses									69,147	66,430	59,473
Franchise tax settlement											12,590
Incentive compensation expense									2,242	10,361	15,340
Other operational expenses									2,360	669	38
Derivative expense, net											0
Total operating expenses									1,055,443	647,266	230,623
Income (loss) from operations									(974,249)	(462,002)	(91,797)
Other (income) expenses:
Interest expense									43,907	38,810	32,816
Interest income									(327)	(333)	(1,480)
Other income									(617)	(836)	(875)
Other expense									434	274
Loss on early extinguishment of debt											27,279
Loss from investment in subsidiaries									231,783	(133,336)	(214,983)
Total other expenses									275,180	(95,421)	(157,243)
Income (loss) before income taxes									(1,249,429)	(366,581)	65,446
Provision (benefit) for income taxes:
Current									(44,096)	159	(10,904)
Deferred									(114,418)	(177,197)	(41,284)
Total income taxes									(158,514)	(177,038)	(52,188)
Net income (loss)									(1,090,915)	(189,543)	117,634
Comprehensive income (loss)									(1,156,278)	(104,166)	86,739
Guarantor Subsidiary [Member]
Operating revenue:
Oil production									403,693	486,403	684,629
Natural gas production									41,863	79,682	121,685
Natural gas liquids production									9,947	24,442	28,394
Other operational income									0	400	645
Derivative income, net									7,952	19,351
Total operating revenue									463,455	610,278	835,353
Operating expenses:
Lease operating expenses									83,872	157,776	186,473
Transportation, processing and gathering expenses									8,600	11,923	13,850
Production taxes									1,246	3,827	8,800
Depreciation, depletion, amortization									157,964	201,693	256,995
Write-down of oil and gas properties									529,354	0
Accretion expense									25,623	28,181	33,203
Salaries, general and administrative expenses									201	4	5
Franchise tax settlement											0
Incentive compensation expense									0	0	0
Other operational expenses									0	193	113
Derivative expense, net											2,090
Total operating expenses									806,860	403,597	501,529
Income (loss) from operations									(343,405)	206,681	333,824
Other (income) expenses:
Interest expense									21	45	21
Interest income									(246)	(192)	(195)
Other income									(1,163)	(1,496)	(1,924)
Other expense									0	0
Loss on early extinguishment of debt											0
Loss from investment in subsidiaries									0	0	0
Total other expenses									(1,388)	(1,643)	(2,098)
Income (loss) before income taxes									(342,017)	208,324	335,922
Provision (benefit) for income taxes:
Current									0	0	0
Deferred									(157,893)	75,020	120,913
Total income taxes									(157,893)	75,020	120,913
Net income (loss)									(184,124)	133,304	215,009
Comprehensive income (loss)									(184,124)	133,304	215,009
Non-Guarantor Subsidiaries [Member]
Operating revenue:
Oil production									0	0	0
Natural gas production									0	0	0
Natural gas liquids production									0	0	0
Other operational income									0	0	0
Derivative income, net									0	0
Total operating revenue									0	0	0
Operating expenses:
Lease operating expenses									3	0	0
Transportation, processing and gathering expenses									0	0	0
Production taxes									0	0	0
Depreciation, depletion, amortization									0	0	0
Write-down of oil and gas properties									47,630	0
Accretion expense									0	0	0
Salaries, general and administrative expenses									36	17	46
Franchise tax settlement											0
Incentive compensation expense									0	0	0
Other operational expenses									0	0	0
Derivative expense, net											0
Total operating expenses									47,669	17	46
Income (loss) from operations									(47,669)	(17)	(46)
Other (income) expenses:
Interest expense									0	0	0
Interest income									(7)	(49)	(20)
Other income									(3)	0	0
Other expense									0	0
Loss on early extinguishment of debt											0
Loss from investment in subsidiaries									47,659	(32)	26
Total other expenses									47,649	(81)	6
Income (loss) before income taxes									(95,318)	64	(52)
Provision (benefit) for income taxes:
Current									0	0	0
Deferred									0	0	0
Total income taxes									0	0	0
Net income (loss)									(95,318)	64	(52)
Comprehensive income (loss)									(95,318)	64	(52)
Eliminations [Member]
Operating revenue:
Oil production									0	0	0
Natural gas production									0	0	0
Natural gas liquids production									0	0	0
Other operational income									0	0	0
Derivative income, net									0	0
Total operating revenue									0	0	0
Operating expenses:
Lease operating expenses									0	0	0
Transportation, processing and gathering expenses									0	0	0
Production taxes									0	0	0
Depreciation, depletion, amortization									0	0	0
Write-down of oil and gas properties									0	0
Accretion expense									0	0	0
Salaries, general and administrative expenses									0	0	0
Franchise tax settlement											0
Incentive compensation expense									0	0	0
Other operational expenses									0	0	0
Derivative expense, net											0
Total operating expenses									0	0	0
Income (loss) from operations									0	0	0
Other (income) expenses:
Interest expense									0	0	0
Interest income									0	0	0
Other income									0	0	0
Other expense									0	0
Loss on early extinguishment of debt											0
Loss from investment in subsidiaries									(279,442)	133,368	214,957
Total other expenses									(279,442)	133,368	214,957
Income (loss) before income taxes									279,442	(133,368)	(214,957)
Provision (benefit) for income taxes:
Current									0	0	0
Deferred									0	0	0
Total income taxes									0	0	0
Net income (loss)									279,442	(133,368)	(214,957)
Comprehensive income (loss)									$ 279,442	$ (133,368)	$ (214,957)