Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Statement of Cash Flows [Abstract]
Net income (loss)	$ (35,720)	$ (176,830)
Net income (loss)	(35,720)	(176,830)
Adjustments to net income (loss) to reconcile to net cash provided by operating activities:
Net change in fair value of unsettled derivatives	68,058	167,218
Depreciation, depletion and amortization	491,784	409,952
Impairment of properties and equipment	37,021	194,230
Accretion of asset retirement obligations	4,503	3,773
Non-cash stock-based compensation	18,124	16,357
(Gain) loss on sale of properties and equipment	9,599	3,199
Amortization of debt discount and issuance costs	10,139	9,454
Deferred income taxes	(4,389)	(53,029)
Other	2,761	1,025
Changes in assets and liabilities	73,845	2,485
Net cash from operating activities	675,725	577,834
Cash flows from investing activities:
Capital expenditures for development of crude oil and natural gas properties	(780,581)	(685,549)
Capital expenditures for other properties and equipment	(15,522)	(3,739)
Acquisition of crude oil and natural gas properties, including settlement adjustments	(12,445)	(181,572)
Proceeds from sale of properties and equipment	1,528	2,443
Proceeds from Divestiture of Businesses	202,046	43,493
Restricted cash	8,001	1,249
Net cash from investing activities	(596,973)	(823,675)
Cash flows from financing activities:
Proceeds from revolving credit facility	1,300,000	629,000
Repayment of revolving credit facility	(1,235,500)	(554,000)
Payments of Debt Issuance Costs	53	4,086
Stock Repurchased and Retired During Period, Value	(142,665)	0
Payments for Repurchase of Common Stock	(3,874)	(4,700)
Finance Lease, Principal Payments	(1,492)	(873)
Other	0	(55)
Net cash from financing activities	(83,584)	65,286
Net change in cash, cash equivalents, and restricted cash	(4,832)	(180,555)
Cash, cash equivalents and restricted cash, beginning of period	9,399	189,925
Cash, cash equivalents and restricted cash, end of period	4,567	9,370
Cash payments (receipts) for:
Interest, net of capitalized interest	41,483	39,470
Income taxes	261	(6,707)
Non-cash investing and financing activities:
Change in accounts payable related to purchases of properties and equipment	(57,696)	91,444
Change in asset retirement obligation, with a corresponding change to crude oil and natural gas properties, net of disposals	$ 13,493	$ 6,720