Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Net income (loss)	$ 36,371	$ (590,451)
Adjustments to reconcile net income (loss) to cash flows from operating activities
Depletion, depreciation, and amortization	154,448	198,919
Write-down of oil and natural gas properties	0	810,921
Deferred income taxes	35,846	(331,574)
Stock-based compensation	12,215	9,682
Commodity derivatives expense (income)	(9,712)	99,811
Receipt (payment) on settlements of commodity derivatives	(38,618)	116,958
Gain on debt extinguishment	0	(115,095)
Debt issuance costs and discounts	4,801	15,541
Other, net	(112)	(3,271)
Changes in assets and liabilities, net of effects from acquisitions
Accrued production receivable	3,590	(2,207)
Trade and other receivables	(13,604)	35,911
Other current and long-term assets	(4,734)	(8,434)
Accounts payable and accrued liabilities	(22,736)	(57,830)
Oil and natural gas production payable	(10,848)	(13,290)
Other liabilities	(4,048)	(6,232)
Net cash provided by operating activities	142,859	159,359
Cash flows from investing activities
Oil and natural gas capital expenditures	(197,982)	(176,631)
Acquisitions of oil and natural gas properties	(91,124)	(560)
Net proceeds from sales of oil and natural gas properties and equipment	1,412	47,232
Other	(6,314)	(4,048)
Net cash used in investing activities	(294,008)	(134,007)
Cash flows from financing activities
Bank repayments	(1,188,000)	(1,362,500)
Bank borrowings	1,382,000	1,447,500
Interest payments on senior secured notes treated as a reduction of debt	(25,139)	0
Repurchases of senior subordinated notes	0	(76,708)
Pipeline financing and capital lease debt repayments	(20,523)	(21,510)
Other	1,262	(11,673)
Net cash provided by (used in) financing activities	149,600	(24,891)
Net increase (decrease) in cash and cash equivalents	(1,549)	461
Cash and cash equivalents at beginning of period	1,606	2,812
Cash and cash equivalents at end of period	$ 57	$ 3,273