Subsidiary Guarantor Condensed Consolidating Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Crude oil, natural gas and NGLs sales	$ 307,409	$ 372,439	$ 967,464	$ 1,003,597
Commodity price risk management gain (loss), net	54,867	(94,394)	(87,858)	(257,760)
Other income	3,667	2,672	11,495	8,011
Revenues	365,943	280,717	891,101	753,848
Lease operating expenses	36,498	33,046	106,047	94,942
Production taxes	13,039	23,984	57,849	66,757
Transportation, gathering and processing expenses	10,999	9,234	34,631	25,511
Exploration, geologic and geophysical expense	(209)	(1,032)	(3,492)	(4,553)
Impairment of properties and equipment	167	1,488	37,021	194,230
General and administrative expense	41,091	48,240	123,497	121,183
Results of Operations, Depreciation, Depletion, Amortization and Accretion	171,839	147,540	491,784	409,952
Accretion of asset retirement obligations	1,356	1,200	4,503	3,773
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	43,872	2,118	9,599	3,199
Other Cost and Expense, Operating	2,492	2,711	8,882	8,187
Costs and Expenses	321,562	270,593	877,305	932,287
Operating Income (Loss)	44,381	10,124	13,796	(178,439)
Interest Expense	(17,859)	(17,622)	(53,742)	(52,561)
Interest income	48	188	63	405
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	26,570	(7,310)	(39,883)	(230,595)
Income tax (expense) benefit	(10,662)	3,876	4,163	53,765
Income (Loss) from Subsidiaries, Net of Tax	0	0	0	0
Net Income (Loss) Attributable to Parent	15,908	(3,434)	(35,720)	(176,830)
Corporate, Non-Segment [Member]
Crude oil, natural gas and NGLs sales	226,397	280,866	737,601	757,263
Commodity price risk management gain (loss), net	54,867	(94,394)	(87,858)	(257,760)
Other income	3,193	2,300	8,381	7,295
Revenues	284,457	188,772	658,124	506,798
Lease operating expenses	23,955	23,219	71,143	68,013
Production taxes	10,787	17,852	44,600	50,122
Transportation, gathering and processing expenses	6,252	4,520	17,561	11,361
Exploration, geologic and geophysical expense	(311)	(279)	(887)	(887)
Impairment of properties and equipment	117	98	117	191
General and administrative expense	37,936	43,886	109,655	108,597
Results of Operations, Depreciation, Depletion, Amortization and Accretion	119,460	97,370	349,055	284,963
Accretion of asset retirement obligations	1,220	1,084	3,949	3,460
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	(227)	(141)	(675)	940
Other Cost and Expense, Operating	2,492	2,711	8,882	8,187
Costs and Expenses	202,303	190,878	605,174	536,721
Operating Income (Loss)	82,154	(2,106)	52,950	(29,923)
Interest Expense	(18,803)	(18,232)	(56,488)	(54,244)
Interest income	48	188	63	405
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	63,399	(20,150)	(3,475)	(83,762)
Income tax (expense) benefit	(19,010)	5,753	(4,087)	19,678
Income (Loss) from Subsidiaries, Net of Tax	(28,481)	10,963	(28,158)	(112,746)
Net Income (Loss) Attributable to Parent	15,908	(3,434)	(35,720)	(176,830)
Reportable Legal Entities [Member]
Crude oil, natural gas and NGLs sales	81,012	91,573	229,863	246,334
Commodity price risk management gain (loss), net	0	0	0	0
Other income	474	372	3,114	716
Revenues	81,486	91,945	232,977	247,050
Lease operating expenses	12,543	9,827	34,904	26,929
Production taxes	2,252	6,132	13,249	16,635
Transportation, gathering and processing expenses	4,747	4,714	17,070	14,150
Exploration, geologic and geophysical expense	(102)	(753)	(2,605)	(3,666)
Impairment of properties and equipment	50	1,390	36,904	194,039
General and administrative expense	3,155	4,354	13,842	12,586
Results of Operations, Depreciation, Depletion, Amortization and Accretion	52,379	50,170	142,729	124,989
Accretion of asset retirement obligations	136	116	554	313
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	44,099	2,259	10,274	(2,259)
Other Cost and Expense, Operating	0	0	0	0
Costs and Expenses	119,259	79,715	272,131	395,566
Operating Income (Loss)	(37,773)	12,230	(39,154)	(148,516)
Interest Expense	(944)	(610)	(2,746)	(1,683)
Interest income	0	0	0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(36,829)	12,840	(36,408)	(146,833)
Income tax (expense) benefit	8,348	(1,877)	8,250	34,087
Income (Loss) from Subsidiaries, Net of Tax	0	0	0	0
Net Income (Loss) Attributable to Parent	(28,481)	10,963	(28,158)	(112,746)
Consolidation, Eliminations [Member]
Crude oil, natural gas and NGLs sales	0	0	0	0
Commodity price risk management gain (loss), net	0	0	0	0
Other income	0	0	0	0
Revenues	0	0	0	0
Lease operating expenses	0	0	0	0
Production taxes	0	0	0	0
Transportation, gathering and processing expenses	0	0	0	0
Exploration, geologic and geophysical expense	0	0	0	0
Impairment of properties and equipment	0	0	0	0
General and administrative expense	0	0	0	0
Results of Operations, Depreciation, Depletion, Amortization and Accretion	0	0	0	0
Accretion of asset retirement obligations	0	0	0	0
GainLossonSaleOfOilAndGasPropertyFromContinuingOperations	0	0	0	0
Other Cost and Expense, Operating	0	0	0	0
Costs and Expenses	0	0	0	0
Operating Income (Loss)	0	0	0	0
Interest Expense	0	0	0	0
Interest income	0	0	0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	0	0	0	0
Income tax (expense) benefit	0	0	0	0
Income (Loss) from Subsidiaries, Net of Tax	28,481	(10,963)	28,158	112,746
Net Income (Loss) Attributable to Parent	$ 28,481	$ (10,963)	$ 28,158	$ 112,746