Chapter 11 Proceedings Chapter 11 Proceedings (Details) - USD ($) $ in Thousands		3 Months Ended
	Apr. 15, 2016	Mar. 31, 2016	Mar. 31, 2015	Apr. 22, 2016	Dec. 31, 2015	Nov. 02, 2015	May. 01, 2015
Plan of Reorganization [Abstract]
Contractual Interest Expense on Prepetition Liabilities Not Recognized in Statement of Operations		$ 17,300
Liabilities Subject to Compromise [Abstract]
Liabilities Subject to Compromise, Accounts Payable and Accrued Liabilities		2,607			$ 55,587
Liabilities Subject to Compromise, Accrued Capital Costs		1,611			7,225
Liabilities Subject to Compromise, Undistributed Oil and Gas Revenues		1,881			11,989
Liabilities Subject to Compromise, Debt and Accrued Interest		905,629			905,629
Liabilities Subject to Compromise, Other Liabilities		6,244			3,958
Liabilities Subject to Compromise		917,972			$ 984,388
Reorganization Items [Abstract]
Debtor Reorganization Items, Legal and Advisory Professional Fees		13,553
Debtor Reorganization Items, Other Expense (Income)		(3,124)
Reorganization Items		$ 10,429	$ 0
Subsequent Event [Member]
Plan of Reorganization [Abstract]
Plan of Reogranization, percentage of common stock lenders to receive net of backstop fee				88.50%
Plan of Reorganization, backstop fee				7.50%
Plan of Reorganization, Percentage of Common Stock existing equity holders to retain				4.00%
Plan or Reorganization, warrants existing equity holders				30.00%
Plan of Reorganization, Percentage of Common Stock Registration Rights Holder to receive				5.00%
Net Proceeds from Texegy Deal	$ 46,900
Fresh Start Accounting Threshold, Required Voting Shares				50.00%
Debtor-in-Possession Financing [Abstract]
Debtor-in-Possession Financing, Amount Arranged				$ 75,000
Liabilities Subject to Compromise [Abstract]
Liabilities Subject to Compromise, Debt and Accrued Interest				905,629
Line of Credit [Member]
Plan of Reorganization [Abstract]
Line of Credit Facility, Current Borrowing Capacity						$ 330,000	$ 375,000
Line of Credit [Member] | New Credit Facility [Member] | Subsequent Event [Member]
Plan of Reorganization [Abstract]
Line of Credit Facility, Current Borrowing Capacity				$ 320,000