UNAUDITED CONDENSED STATEMENTS OF CONSOLIDATED CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ (31,477)	$ 3,239
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	11,166	12,958
(Gain) loss on derivative instruments	32,393	10,456
Cash settlements (paid) received on expired derivative instruments	(1,277)	4,876
Bad debt expense	101	0
Amortization of deferred financing costs	308	541
Accretion of asset retirement obligations	1,311	1,718
(Gain) loss on sale of properties	0	2,373
Share-based compensation (see Note 11)	1,443	1,176
Settlement of asset retirement obligations	(162)	0
Changes in operating assets and liabilities:
Accounts receivable	4,326	2,839
Prepaid expenses and other assets	(6,856)	(115)
Payables and accrued liabilities	(537)	2,086
Other	61	0
Net cash provided by operating activities	10,800	42,147
Cash flows from investing activities:
Additions to oil and gas properties	(10,370)	(13,098)
Additions to other property and equipment	(62)	0
Additions to restricted investments	(68)	(186)
Net cash used in investing activities	(10,500)	(13,284)
Cash flows from financing activities:
Advances on revolving credit facilities	0	5,000
Payments on revolving credit facilities	(24,000)	(34,000)
Deferred financing costs	(101)	0
Costs incurred in conjunction with tender offer	(107)	0
Common stock repurchased and retired under the share repurchase program	(920)	0
Other	0	(213)
Net cash used in financing activities	(25,128)	(29,213)
Net change in cash, cash equivalents and restricted cash	(24,828)	(350)
Cash, cash equivalents and restricted cash, beginning of period	50,029	6,392
Cash, cash equivalents and restricted cash, end of period	$ 25,201	$ 6,042