Summary of Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Jul. 15, 2014	Dec. 31, 2013
Property and Equipment
Proved oil and gas properties	$ 5,755,886			$ 5,755,886				$ 5,600,279
Unproved oil and gas properties	65,767			65,767				71,452
Furniture, fixtures, and other equipment	41,997			41,997				42,368
Less - Accumulated depreciation, depletion, and amortization	(3,326,908)			(3,326,908)				(3,125,282)
Property and Equipment, Net	2,536,742			2,536,742				2,588,817
Accounts Payable and Accrued Liabilities
Trade accounts payable	25,624	[1]		25,624	[1]			30,769	[1]
Accrued operating expenses	14,451			14,451				16,016
Accrued payroll costs	11,212			11,212				10,938
Asset retirement obligation - current portion	13,292			13,292				15,859
Accrued taxes	9,626			9,626				5,845
Deferred liability	22,685	[2]		22,685	[2]		12,500	0	[2]
Other payables	3,603			3,603				2,891
Total accounts payable and accrued liabilities	100,493			100,493				82,318
Roll-forward of our asset retirement obligation
Asset Retirement Obligation recorded as of January 1				79,084
Accretion expense	1,445		1,478	4,246		4,732
Liabilities incurred for new wells and facilities construction				470
Reductions due to sold and abandoned wells				(2,914)
Revisions in estimates				(439)
Asset Retirement Obligation	$ 80,447			$ 80,447
Year 2014 [Member] | Natural Gas Derivative Contract [Member] | Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Future Gas Production Hedged in MMBTU (Energy Item Type)	3,330,000			3,330,000
Derivative, Swap Type, Average Fixed Price	4.32			4.32
Year 2014 [Member] | Natural Gas Derivative Contract [Member] | Collar [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Future Gas Production Hedged in MMBTU (Energy Item Type)	1,035,000			1,035,000
Derivative, Average Floor Price	4.15			4.15
Derivative, Average Cap Price	4.55			4.55
Year 2014 [Member] | Natural Gas Basis Derivative Contract [Member] | Basis Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Future Gas Production Hedged in MMBTU (Energy Item Type)	4,200,000			4,200,000
Derivative, Swap Type, Average Fixed Price	(0.11)			(0.11)
Year 2015 [Member] | Natural Gas Derivative Contract [Member] | Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Future Gas Production Hedged in MMBTU (Energy Item Type)	900,000			900,000
Derivative, Swap Type, Average Fixed Price	4.42			4.42
Year 2015 [Member] | Natural Gas Basis Derivative Contract [Member] | Basis Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Future Gas Production Hedged in MMBTU (Energy Item Type)	8,200,000			8,200,000
Derivative, Swap Type, Average Fixed Price	(0.02)			(0.02)

[1] Included in “trade accounts payable” are liabilities of approximately $9.6 million and $26.1 million at September 30, 2014 and December 31, 2013, respectively, for outstanding checks.

[2] This amount equals the liability related to funds received from Saka Energi that are maintained in a restricted cash account. Refer to the "Short-Term Restricted Cash" discussion below for further information.