CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 12, 2016	Dec. 31, 2018	Dec. 31, 2017
Cash and cash equivalents - beginning of period	$ 31,414		$ 11,017
Cash and cash equivalents - end of period		$ 31,414	17,864	$ 11,017
Successor [Member]
Net increase (decrease) in cash and cash equivalents	(24,653)		6,847	4,256
Cash and cash equivalents - beginning of period	31,414		11,017	6,761
Cash and cash equivalents - end of period	6,761	31,414	17,864	11,017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	(5,296)		224,785	32,662
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Non-cash reorganization items	0		(3,322)	0
Depreciation, depletion and amortization	11,652		127,961	48,649
Accretion of firm transportation obligation	0		0	0
Derivative contracts:
Net (gains) losses	16,622		(37,427)	17,819
Cash settlements, net	384		(48,291)	(3,511)
Deferred income tax expense (benefit)	0		2,994	(4,943)
Loss (gain) on sales of assets, net	49		177	36
Non-cash exploration expense	0		0	0
Non-cash interest expense	226		3,416	2,122
Share-based compensation (equity-classified)	81		4,618	3,809
Other, net	21		44	61
Changes in operating assets and liabilities:
Accounts receivable, net	10,791		(23,674)	(43,318)
Accounts payable and accrued expenses	(3,887)		21,109	28,542
Other assets and liabilities	131		(258)	(218)
Net cash provided by operating activities	30,774		272,132	81,710
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisitions, net	0		(85,387)	(200,849)
Capital expenditures	(4,812)		(430,592)	(115,687)
Proceeds from sales of assets, net	0		7,683	869
Other, net	(104)		0	0
Net cash used in investing activities	(4,916)		(508,296)	(315,667)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from credit facility borrowings	0		244,000	59,000
Repayment of credit facility borrowings	(50,350)		0	(7,000)
Proceeds from second line note	0		0	196,000
Debt issuance costs paid	0		(989)	(9,787)
Proceeds received from rights offering, net	0		0	55
Other, net	(161)		0	(55)
Net cash provided by (used in) financing activities	(50,511)		243,011	238,213
Cash paid for:
Cash paid for interest (net of amounts capitalized)	598		22,599	4,102
Cash paid for income taxes (net of refunds)	(7)		0	0
Cash paid for reorganization items, net	525		540	954
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Common stock issued in exchange for liabilities	0		0	0
Changes in accrued liabilities related to capital expenditures	(997)		(44)	(19,910)
Derivatives settled to reduce outstanding debt	0		$ 0	$ 0
Predecessor [Member]
Net increase (decrease) in cash and cash equivalents		19,459
Cash and cash equivalents - beginning of period	$ 31,414	11,955
Cash and cash equivalents - end of period		31,414
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)		1,054,602
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Non-cash reorganization items		(1,178,302)
Depreciation, depletion and amortization		33,582
Accretion of firm transportation obligation		317
Derivative contracts:
Net (gains) losses		8,333
Cash settlements, net		48,008
Deferred income tax expense (benefit)		0
Loss (gain) on sales of assets, net		(1,261)
Non-cash exploration expense		6,038
Non-cash interest expense		22,189
Share-based compensation (equity-classified)		1,511
Other, net		(13)
Changes in operating assets and liabilities:
Accounts receivable, net		12,273
Accounts payable and accrued expenses		22,469
Other assets and liabilities		501
Net cash provided by operating activities		30,247
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisitions, net		0
Capital expenditures		(15,359)
Proceeds from sales of assets, net		224
Other, net		1,186
Net cash used in investing activities		(13,949)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from credit facility borrowings		75,350
Repayment of credit facility borrowings		(119,121)
Proceeds from second line note		0
Debt issuance costs paid		(3,011)
Proceeds received from rights offering, net		49,943
Other, net		0
Net cash provided by (used in) financing activities		3,161
Cash paid for:
Cash paid for interest (net of amounts capitalized)		4,331
Cash paid for income taxes (net of refunds)		(35)
Cash paid for reorganization items, net		30,990
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Common stock issued in exchange for liabilities		140,952
Changes in accrued liabilities related to capital expenditures		(11,301)
Derivatives settled to reduce outstanding debt		$ 51,979