Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
OPERATING ACTIVITIES:
Net income (loss)	$ 28,693	$ (137,307)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion, and amortization	151,545	158,437
Impairments (Note 2)	0	161,563
Amortization of debt issuance costs and debt discount (Note 6)	1,616	1,586
(Gain) loss on derivatives	(21,019)	4,774
Cash (payments) receipts on derivatives settled, net	(729)	11,735
Deferred tax expense (benefit)	22,084	(73,159)
Gain on disposition of assets	(1,153)	(1,100)
Stock compensation plans	12,478	10,664
Other, net	1,397	(3,055)
Changes in operating assets and liabilities increasing (decreasing) cash:
Accounts receivable	(36,381)	759
Accounts payable	4,873	26,940
Material and supplies	17	231
Accrued liabilities	20,280	14,073
Income taxes	(15)	20,636
Other, net	1,106	985
Net cash provided by operating activities	184,792	197,762
INVESTING ACTIVITIES:
Capital expenditures	(167,392)	(154,558)
Producing properties and other acquisitions (Note 3)	(55,429)	0
Proceeds from disposition of assets	20,137	46,880
Other	(1,500)	169
Net cash used in investing activities	(204,184)	(107,509)
FINANCING ACTIVITIES:
Borrowings under credit agreement	251,401	195,700
Payments under credit agreement	(250,100)	(261,700)
Payments on capitalized leases	(2,967)	(2,756)
Proceeds from common stock issued, net of issue costs (Note 13)	18,623	0
Tax benefit from stock compensation	0	(376)
Book overdrafts	2,364	(21,043)
Net cash provided by (used in) financing activities	19,321	(90,175)
Net increase (decrease) in cash and cash equivalents	(71)	78
Cash and cash equivalents, beginning of period	893	835
Cash and cash equivalents, end of period	822	913
Cash paid during the year for:
Interest paid (net of capitalized)	14,601	16,650
Income taxes	0	0
Changes in accounts payable and accrued liabilities related to purchases of property, plant, and equipment	(20,122)	36,934
Non-cash (addition) reduction to oil and natural gas properties related to asset retirement obligations	$ (3,203)	$ 29,423