Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities
Net loss	$ (590,451)	$ (3,500,371)
Adjustments to reconcile net loss to cash flows from operating activities
Depletion, depreciation, and amortization	198,919	419,304
Write-down of oil and natural gas properties	810,921	3,612,600
Impairment of goodwill	0	1,261,512
Deferred income taxes	(331,574)	(1,432,572)
Stock-based compensation	9,682	22,637
Commodity derivatives expense (income)	99,811	(126,178)
Receipt on settlements of commodity derivatives	116,958	433,293
Gain on debt extinguishment	(115,095)	0
Debt issuance costs and discounts	15,541	6,810
Other, net	(3,271)	(7,457)
Changes in assets and liabilities, net of effects from acquisitions
Accrued production receivable	(2,207)	57,867
Trade and other receivables	35,911	37,463
Other current and long-term assets	(8,434)	(1,771)
Accounts payable and accrued liabilities	(57,830)	(53,124)
Oil and natural gas production payable	(13,290)	(26,478)
Other liabilities	(6,232)	(4,138)
Net cash provided by operating activities	159,359	699,397
Cash flows from investing activities
Oil and natural gas capital expenditures	(176,631)	(364,948)
Acquisitions of oil and natural gas properties	(560)	(21,171)
CO2 capital expenditures	(467)	(21,894)
Pipelines and plants capital expenditures	(2,881)	(25,767)
Net proceeds from sales of oil and natural gas properties and equipment	47,232	327
Other	(700)	5,913
Net cash used in investing activities	(134,007)	(427,540)
Cash flows from financing activities
Bank repayments	(1,362,500)	(1,491,000)
Bank borrowings	1,447,500	1,306,000
Repurchases of senior subordinated notes	(76,708)	0
Pipeline financing and capital lease debt repayments	(21,510)	(25,638)
Cash dividends paid	(478)	(65,422)
Other	(11,195)	(6,738)
Net cash provided by (used in) financing activities	(24,891)	(282,798)
Net increase (decrease) in cash and cash equivalents	461	(10,941)
Cash and cash equivalents at beginning of period	2,812	23,153
Cash and cash equivalents at end of period	$ 3,273	$ 12,212