Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
OPERATING ACTIVITIES:
Net income	$ 7,865	$ 15,929
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization	57,066	46,932
Amortization of debt issuance costs and debt discount (Note 6)	546	536
(Gain) loss on derivatives	6,762	(14,731)
Cash payments on derivatives settled, net	(2,073)	(1,159)
Deferred tax expense	3,607	13,936
Gain on disposition of assets	(161)	(824)
Stock compensation plans	6,609	3,704
Contract assets and liabilities, net (Note 2)	(1,192)	0
Other, net	937	626
Changes in operating assets and liabilities increasing (decreasing) cash:
Accounts receivable	8,005	(1,900)
Accounts payable	(10,716)	(7,735)
Material and supplies	50	73
Accrued liabilities	6,757	9,832
Other, net	(494)	433
Net cash provided by operating activities	83,568	65,652
INVESTING ACTIVITIES:
Capital expenditures	(90,249)	(37,636)
Producing properties and other acquisitions	0	(7,508)
Proceeds from disposition of assets	22,084	16,116
Net cash used in investing activities	(68,165)	(29,028)
FINANCING ACTIVITIES:
Borrowings under credit agreement	67,400	49,700
Payments under credit agreement	(97,700)	(60,500)
Payments on capitalized leases	(946)	(946)
Book overdrafts	15,894	(17,301)
Net cash used in financing activities	(15,352)	(29,047)
Net increase in cash and cash equivalents	51	7,577
Cash and cash equivalents, beginning of period	701	893
Cash and cash equivalents, end of period	752	8,470
Cash paid during the year for:
Interest paid (net of capitalized)	(1,731)	(2,389)
Income taxes	0	0
Changes in accounts payable and accrued liabilities related to purchases of property, plant, and equipment	(13,238)	(11,401)
Non-cash (addition) reduction to oil and natural gas properties related to asset retirement obligations	$ 6,340	$ 912