Subsidiary Guarantor Condensed Consolidating Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Crude oil, natural gas, and NGLs sales	$ 305,225	$ 189,692
Commodity price risk management gain (loss), net	(47,240)	80,704
Other income	2,615	3,311
Revenues	260,600	273,707
Lease operating expenses	29,636	19,789
Production taxes	20,169	12,399
Transportation, gathering, and processing expenses	7,313	5,902
Exploration, geologic, and geophysical expense	2,646	954
Impairment of properties and equipment	33,188	2,193
General and administrative expense	35,696	26,315
Results of Operations, Depreciation, Depletion, Amortization and Accretion	126,788	109,316
Accretion of asset retirement obligations	1,288	1,768
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	(1,432)	160
Other Cost and Expense, Operating	2,768	3,528
Costs and Expenses	260,924	182,004
Operating Income (Loss)	(324)	91,703
Interest Expense	17,529	19,467
Interest income	148	240
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(17,705)	72,476
Income tax (expense) benefit	4,566	(26,330)
Income (Loss) from Subsidiaries, Net of Tax	0	0
Net Income (Loss) Attributable to Parent	(13,139)	46,146
Corporate, Non-Segment [Member]
Crude oil, natural gas, and NGLs sales	233,494	170,739
Commodity price risk management gain (loss), net	(47,240)	80,704
Other income	2,516	3,297
Revenues	188,770	254,740
Lease operating expenses	21,362	15,816
Production taxes	16,081	11,144
Transportation, gathering, and processing expenses	3,231	5,215
Exploration, geologic, and geophysical expense	313	271
Impairment of properties and equipment	6	604
General and administrative expense	31,559	23,529
Results of Operations, Depreciation, Depletion, Amortization and Accretion	94,376	101,738
Accretion of asset retirement obligations	1,200	1,685
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	(1,432)	160
Other Cost and Expense, Operating	2,768	3,528
Costs and Expenses	172,328	163,370
Operating Income (Loss)	16,442	91,370
Interest Expense	18,097	19,597
Interest income	148	240
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(1,507)	72,013
Income tax (expense) benefit	577	(26,162)
Income (Loss) from Subsidiaries, Net of Tax	(12,209)	295
Net Income (Loss) Attributable to Parent	(13,139)	46,146
Reportable Legal Entities [Member]
Crude oil, natural gas, and NGLs sales	71,731	18,953
Commodity price risk management gain (loss), net	0	0
Other income	99	14
Revenues	71,830	18,967
Lease operating expenses	8,274	3,973
Production taxes	4,088	1,255
Transportation, gathering, and processing expenses	4,082	687
Exploration, geologic, and geophysical expense	2,333	683
Impairment of properties and equipment	33,182	1,589
General and administrative expense	4,137	2,786
Results of Operations, Depreciation, Depletion, Amortization and Accretion	32,412	7,578
Accretion of asset retirement obligations	88	83
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	0	0
Other Cost and Expense, Operating	0	0
Costs and Expenses	88,596	18,634
Operating Income (Loss)	(16,766)	333
Interest Expense	(568)	(130)
Interest income	0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(16,198)	463
Income tax (expense) benefit	3,989	(168)
Income (Loss) from Subsidiaries, Net of Tax	0	0
Net Income (Loss) Attributable to Parent	(12,209)	295
Consolidation, Eliminations [Member]
Crude oil, natural gas, and NGLs sales	0	0
Commodity price risk management gain (loss), net	0	0
Other income	0	0
Revenues	0	0
Lease operating expenses	0	0
Production taxes	0	0
Transportation, gathering, and processing expenses	0	0
Exploration, geologic, and geophysical expense	0	0
Impairment of properties and equipment	0	0
General and administrative expense	0	0
Results of Operations, Depreciation, Depletion, Amortization and Accretion	0	0
Accretion of asset retirement obligations	0	0
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	0	0
Other Cost and Expense, Operating	0	0
Costs and Expenses	0	0
Operating Income (Loss)	0	0
Interest Expense	0	0
Interest income	0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	0	0
Income tax (expense) benefit	0	0
Income (Loss) from Subsidiaries, Net of Tax	12,209	(295)
Net Income (Loss) Attributable to Parent	$ 12,209	$ (295)