Oil and Gas Properties (Income (Loss) From Discontinued Operations) (Details) (USD $)	3 Months Ended							12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of tax	$ 44,000	$ (29,000)	$ 1,058,000	$ (71,888,000)	$ 4,503,000	$ 42,216,000	$ 48,853,000	$ 1,073,000		$ 23,684,000		$ 95,221,000
Net interest expense								32,898,000		48,160,000		70,181,000
Impairment of Oil and Gas Properties										138,600,000
Energy Resource Technology GOM, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues								48,847,000	[1]	557,231,000		696,607,000
Production (lifting) costs								16,017,000	[1]	164,663,000		176,269,000
Hurricane repair expense										662,000		(4,838,000)
Exploration expense								3,514,000	[1]	3,295,000		10,914,000
Depreciation, depletion, amortization and accretion								1,226,000	[1]	158,284,000		219,915,000
Proved property impairment and abandonment								(152,000)	[1],[2]	151,045,000	[2]	113,439,000	[2]
(Gain) loss on sale of oil and gas properties										1,714,000		(4,531,000)
Hedge ineffectiveness and non-hedge gain on commodity derivative contracts										(5,550,000)
Selling, general and administrative expense								1,229,000	[1]	17,823,000		12,951,000
Net interest expense and other								2,732,000	[1],[3]	28,191,000	[3]	25,558,000	[3]
Total costs								24,566,000	[1]	520,127,000		549,677,000
Pretax income from discontinued operations								24,281,000	[1]	37,104,000		146,930,000
Income tax provision								8,499,000	[1]	13,420,000		51,709,000
Income from operations of discontinued operations								15,782,000	[1]	23,684,000		95,221,000
Loss on sale of business, net of tax								(14,709,000)	[1]
Income (loss) from discontinued operations, net of tax								1,073,000	[1]	23,684,000		95,221,000
Net interest expense								$ 2,700,000		$ 27,700,000		$ 25,200,000

[1] Results for 2013 reflect the operating results from January 1, 2013 through February 6, 2013 when ERT was sold. There were no material results of operations for our former oil and gas segment subsequent to the sale of ERT.

[2] Results for 2012 include a charge of $138.6 million to reduce our carrying value of ERT to its estimated fair value less costs to sell.

[3] Net interest expense of $2.7 million, $27.7 million and $25.2 million for the years ended December 31, 2013, 2012 and 2011, respectively, was allocated to ERT and primarily consisted of interest associated with indebtedness directly attributed to the substantial oil and gas acquisition made in 2006. This includes interest related to debt required to be repaid upon the disposition of ERT.