Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Activities [Abstract]
Net Income (Loss)	$ (89,698)	$ (21,831)
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depletion, depreciation and amoritzation	31,753	30,848
Unrealized Gain (Loss) on Derivatives	13,218	0
Deferred gain on sale of liquids gathering system	(2,638)	(2,638)
Amounts charged against income before income tax benefit	851	1,797
Non-cash reorganization items, net	43,576	0
Other	173	4,063
Increase (Decrease) in Operating Capital [Abstract]
Restricted cash	(76)	(1,135)
Accounts receivable	14,680	10,940
Other current assets	203	(15,121)
Accounts payable	22,968	(50,867)
Accrued liabilities	38,691	(9,970)
Production taxes payable	18,512	(859)
Interest payable	85,339	42,253
Other long-term obligations	(8,292)	9,020
Income taxes payable receivable	2,099	(190)
Net Cash Provided by (Used in) Operating Activities	171,359	(3,690)
Investing Activities [Abstract]
Oil and gas property expenditures	(89,360)	(76,672)
Change in capital cost accrual	(919)	(11,092)
Inventory	(2,302)	(8)
Purchase of Capital Assets	(234)	132
Net Cash Provided by (Used in) Investing Activities	(92,815)	(87,640)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Borrowings on long-term debt	0	369,000
Repurchased shares - net share settlements	(44)	(307)
Net Cash Provided by (Used in) Financing Activities	(44)	368,693
Cash and Cash Equivalents, Period Increase (Decrease)	78,500	277,363
Cash and Cash Equivalents, at Carrying Value	401,478	4,143
Cash and Cash Equivalents, at Carrying Value	$ 479,978	$ 281,506