CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income (loss)		$ (22,576)	$ (596,544)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization		213,259	283,722
Stock-based compensation expense - equity awards		32,299	16,164
Stock-based compensation expense - liability awards		19,950	0
Impairment and abandonment expense		26,111	650,629
Deferred tax expense (benefit)		0	(85,124)
Net (gain) loss on sale of long-lived assets		254	(388)
Non-cash portion of derivative (gain) loss		61,490	(1,103)
Amortization of debt issuance costs and debt discount		3,935	4,112
(Gain) loss on extinguishment of debt		22,156	(143,443)
Changes in operating assets and liabilities:
(Increase) decrease in accounts receivable		(42,998)	48,139
(Increase) decrease in prepaid and other assets		1,803	(2,825)
Increase (decrease) in accounts payable and other liabilities		17,449	(43,107)
Net cash provided by operating activities		333,132	130,232
Cash flows from investing activities:
Acquisition of oil and natural gas properties		(4,285)	(7,689)
Drilling and development capital expenditures		(215,358)	(300,660)
Purchases of other property and equipment		(686)	(1,035)
Proceeds from sales of oil and natural gas properties		4,011	1,375
Net cash used in investing activities		(216,318)	(308,009)
Cash flows from financing activities:
Proceeds from borrowings under revolving credit facility		450,000	490,000
Repayment of borrowings under revolving credit facility		(575,000)	(310,000)
Proceeds from issuance of convertible senior notes		170,000	0
Debt issuance costs		(6,421)	(6,650)
Premiums paid on capped call transactions		(14,688)	0
Repayments of Senior Debt		(127,073)	0
Proceeds from Stock Options Exercised		15	0
Restricted stock used for tax withholdings		(14,459)	(598)
Net cash (used in) provided by financing activities		(117,626)	172,752
Net increase (decrease) in cash, cash equivalents and restricted cash		(812)	(5,025)
Cash, cash equivalents and restricted cash, beginning of period		8,339	15,543
Cash, cash equivalents and restricted cash, end of period		7,527	10,518
Supplemental cash flow information
Cash paid for interest		40,548	48,331
Supplemental non-cash activity
Accrued capital expenditures included in accounts payable and accrued expenses		44,591	13,593
Asset retirement obligations incurred, including revisions to estimates		110	579
Senior Secured Notes issued in the debt exchange, net of debt discount		0	106,030
Restricted Cash and Cash Equivalents [Abstract]
Cash and cash equivalents		4,985	5,177
Restricted cash(1)	[1]	2,542	5,341
Total cash, cash equivalents and restricted cash		7,527	10,518
Senior Notes Due 2026 | Senior Notes
Supplemental non-cash activity
Notes Reduction		0	108,632
Senior Notes Due 2027 | Senior Notes
Supplemental non-cash activity
Notes Reduction		$ 0	$ 140,840

[1] Included in Prepaid and other current assets and Other noncurrent assets line items in the consolidated balance sheets.