Supplemental Oil and Gas Disclosures (Unaudited) (Details 1) (USD $)	1 Months Ended	12 Months Ended
	Jul. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Costs Incurred in Acquisition, Exploration, and Development Activities Detail [Table]
Acquisition	$ 6,700,000	$ 141,000	$ 5,497,000	$ 2,993,000
Exploration		0	16,822,000	6,820,000
Development		5,798,000	87,465,000	38,806,000
Total costs incurred		5,939,000	109,784,000	48,619,000
Reclassification of capitalized exploration costs				5,000,000
Capitalized Costs Related to Producing Activities Detail [Table]
Undeveloped properties		12,954,000
Proved developed properties being amortized		757,663,000
Total capitalized costs		770,617,000
Less accumulated depletion, depreciation, and amortization		(501,048,000)
Net capitalized costs		269,569,000
Results of Operations for Producing Activities Detail [Table]
Oil and gas sales revenues		81,941,000	197,841,000	174,191,000
Production (lifting) costs		33,496,000	71,066,000	79,115,000
Depreciation, depletion, and amortization		27,640,000	73,679,000	79,610,000
Impairments of properties		15,233,000	63,774,000	11,410,000
Excess decommissioning and abandonment costs		78,382,000	53,997,000	23,771,000
Exploration expenses		77,000	306,000	151,000
Accretion expense		3,705,000	5,008,000	7,717,000
Dry hole costs		(32,000)	325,000	0
Gain on insurance recoveries		0	(2,541,000)	(45,391,000)
Pretax income (loss) from producing activities		(76,560,000)	(67,773,000)	17,808,000
Income tax expense (benefit)		(26,797,000)	(25,186,000)	6,551,000
Results of oil and gas producing activities		(49,763,000)	(42,587,000)	11,257,000
Hurricane related repair expenses				$ 8,200,000
Aggregate percentage of sold reserves		95.00%