Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities
Net loss	$ (45,229)	$ (21,993)	$ (148,769)	$ (33,435)
Adjustments to reconcile net loss to net cash provided by operating activities
Depreciation, depletion and amortization	30,282	20,407	53,997	41,513
Derivative losses	(17,734)	32,286	33,282	48,787
Impairment of oil and gas assets	63,593	0	113,315	0
Impairment of other assets	6,407	0	6,407	0
(Gain) loss on sale of assets	(491)	(469)	(490)	575
Other			1,621	3,578
Change in assets and liabilities
Accounts receivable			13,584	(7,660)
Inventories			40	(3,162)
Prepaid expenses and other assets			1,055	286
Accounts payable and accrued liabilities			(18,389)	(4,221)
Revenue distribution payable			600	7,243
Deferred compensation			1,852	6,566
Net cash provided by operating activities			58,105	60,070
Cash flows from investing activities
Expenditures for property, plant, and equipment and oil and natural gas properties			(146,434)	(176,275)
Proceeds from asset dispositions			857	6,591
Proceeds from (payments on) derivative instruments, net			653	(9,769)
Net cash used in investing activities			(144,924)	(179,453)
Cash flows from financing activities
Proceeds from long-term debt			85,000	116,000
Repayment of long-term debt			(343)	(243,391)
Proceeds from Senior Notes			0	300,000
Principal payments under financing lease obligations			(1,445)	(1,329)
Payment of debt issuance costs and other financing fees			(20)	(6,316)
Treasury stock purchased			(1,171)	(4,872)
Net cash provided by financing activities			82,021	160,092
Net (decrease) increase in cash and cash equivalents			(4,798)	40,709
Cash and cash equivalents, at beginning of period			37,446	27,732
Cash and cash equivalents, at end of period	$ 32,648	$ 68,441	$ 32,648	$ 68,441