CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ (310,557,000)	$ 70,589,000	$ 224,785,000
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Non-cash reorganization items	0	0	(3,322,000)
Depreciation, depletion and amortization	140,673,000	174,569,000	127,961,000
Asset Impairment Charges	391,849,000	0	0
Derivative contracts:
Net (gains) losses	(88,422,000)	68,131,000	(37,427,000)
Cash Settlements Derivatives, Operating Activities	(78,087,000)	4,136,000	48,291,000
Deferred income tax expense (benefit)	(1,424,000)	3,373,000	2,994,000
Loss (gain) on sales of assets, net	(18,000)	(5,000)	177,000
Noncash Interest Expense	4,150,000	3,354,000	3,416,000
Share-based compensation	3,284,000	4,082,000	4,618,000
Other, net	31,000	52,000	44,000
Changes in operating assets and liabilities:
Accounts receivable, net	28,078,000	(5,079,000)	(23,674,000)
Accounts payable and accrued expenses	(24,731,000)	4,690,000	21,109,000
Other assets and liabilities	778,000	574,000	(258,000)
Net cash provided by operating activities	221,778,000	320,194,000	272,132,000
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisitions, net	0	(6,516,000)	(85,387,000)
Capital expenditures	(168,565,000)	(362,743,000)	(430,592,000)
Proceeds from sales of assets, net	87,000	215,000	7,683,000
Net cash used in investing activities	(168,478,000)	(369,044,000)	(508,296,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from credit facility borrowings	51,000,000	76,400,000	244,000,000
Repayment of credit facility borrowings	(99,000,000)	(35,000,000)	0
Debt issuance costs paid	(78,000)	(2,616,000)	(989,000)
Net cash provided by (used in) financing activities	(48,078,000)	38,784,000	243,011,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total	5,222,000	(10,066,000)	6,847,000
Cash and cash equivalents - beginning of period	7,798,000	17,864,000	11,017,000
Cash and cash equivalents - end of period	13,020,000	7,798,000	17,864,000
Cash paid for:
Interest, net of amounts capitalized	27,333,000	32,398,000	22,599,000
Income taxes, net of (refunds)	(2,471,000)	(2,471,000)	0
Reorganization items, net	0	79,000	540,000
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Increase (Decrease) in Accounts Receivable, Acquisitions	0	(152,000)	(27,107,000)
Increase (Decrease) in Other Assets, Acquisitions	0	0	(743,000)
Increase (Decrease) in Accrued Liabilities, Acquisitions	0	(540,000)	(11,182,000)
Capital Expenditures, Period Increase (Decrease)	(18,671,000)	(3,602,000)	44,000
Increase (Decrease) in ARO, Acquisitions	$ 0	$ 83,000	$ 385,000