Subsidiary Guarantor Condensed Consolidating Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Crude oil, natural gas and NGLs sales	$ 321,099	$ 305,225
Commodity price risk management loss, net	(190,074)	(47,240)
Other income	3,475	2,615
Revenues	134,500	260,600
Lease operating expenses	35,221	29,636
Production taxes	22,168	20,169
Transportation, gathering and processing expenses	11,424	7,313
Exploration, geologic and geophysical expense	2,643	2,646
Impairment of properties and equipment	7,875	33,188
General and administrative expense	39,598	35,696
Results of Operations, Depreciation, Depletion, Amortization and Accretion	151,422	126,788
Accretion of asset retirement obligations	1,584	1,288
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	(369)	1,432
Other Cost and Expense, Operating	3,554	2,768
Costs and Expenses	275,120	260,924
Operating Income (Loss)	(140,620)	(324)
Interest Expense	16,978	17,529
Interest income	10	148
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(157,588)	(17,705)
Income tax (expense) benefit	37,412	4,566
Income (Loss) from Subsidiaries, Net of Tax	0	0
Net Income (Loss) Attributable to Parent	(120,176)	(13,139)
Corporate, Non-Segment [Member]
Crude oil, natural gas and NGLs sales	254,849	233,494
Commodity price risk management loss, net	(190,074)	(47,240)
Other income	2,633	2,516
Revenues	67,408	188,770
Lease operating expenses	23,634	21,362
Production taxes	15,885	16,081
Transportation, gathering and processing expenses	5,440	3,231
Exploration, geologic and geophysical expense	317	313
Impairment of properties and equipment	0	6
General and administrative expense	34,434	31,559
Results of Operations, Depreciation, Depletion, Amortization and Accretion	112,631	94,376
Accretion of asset retirement obligations	1,378	1,200
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	(382)	1,432
Other Cost and Expense, Operating	3,554	2,768
Costs and Expenses	196,891	172,328
Operating Income (Loss)	(129,483)	16,442
Interest Expense	17,935	18,097
Interest income	10	148
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(147,408)	(1,507)
Income tax (expense) benefit	34,991	577
Income (Loss) from Subsidiaries, Net of Tax	(7,759)	(12,209)
Net Income (Loss) Attributable to Parent	(120,176)	(13,139)
Reportable Legal Entities [Member]
Crude oil, natural gas and NGLs sales	66,250	71,731
Commodity price risk management loss, net	0	0
Other income	842	99
Revenues	67,092	71,830
Lease operating expenses	11,587	8,274
Production taxes	6,283	4,088
Transportation, gathering and processing expenses	5,984	4,082
Exploration, geologic and geophysical expense	2,326	2,333
Impairment of properties and equipment	7,875	33,182
General and administrative expense	5,164	4,137
Results of Operations, Depreciation, Depletion, Amortization and Accretion	38,791	32,412
Accretion of asset retirement obligations	206	88
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	13	0
Other Cost and Expense, Operating	0	0
Costs and Expenses	78,229	88,596
Operating Income (Loss)	(11,137)	(16,766)
Interest Expense	957	568
Interest income	0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(10,180)	(16,198)
Income tax (expense) benefit	2,421	3,989
Income (Loss) from Subsidiaries, Net of Tax	0	0
Net Income (Loss) Attributable to Parent	(7,759)	(12,209)
Consolidation, Eliminations [Member]
Crude oil, natural gas and NGLs sales	0	0
Commodity price risk management 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	7,759	12,209
Net Income (Loss) Attributable to Parent	$ 7,759	$ 12,209