Oil and Gas Properties (Income (Loss) From Discontinued Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Exploration expense													$ 3,295		$ 10,914		$ 8,276
Income (loss) from discontinued operations, net of tax	(71,888)	[1]	4,503	[1]	42,216	[1]	48,853	[1]	(734)	30,017	30,766	35,172	23,684		95,221		(106,657)
Helix [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of tax													(1,621)
Energy Resource Technology GOM, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues													557,231		696,607		425,369
Production (lifting) costs													164,663		176,269		131,156
Hurricane repair expense													662		(4,838)		4,699
Exploration expense													3,295	[2]	10,914	[2]	8,276	[2]
Depreciation, depletion, amortization and accretion													158,284		219,915		235,243
Proved property impairment charges and other													151,045	[3]	113,439	[3]	177,138	[3]
(Gain) loss on sale of oil and gas properties													1,714		(4,531)		(287)
(Gain) loss on oil and gas derivative contracts													(5,550)				(1,088)
Selling and administrative expense													17,823		12,951		15,966
Interest expense, net and other													28,191	[4]	25,558	[4]	19,687	[4]
Total costs													520,127		549,677		590,790
Pretax income (loss) from discontinued operations													37,104		146,930		(165,421)
DiscontinuedOperationTaxEffectOfDiscontinuedOperation													13,420		51,709		(58,764)
Income (loss) from discontinued operations, net of tax													$ 23,684		$ 95,221		$ (106,657)

[1] Our net loss in the fourth quarter of 2012 includes a $138.6 million impairment charge associated with the sale of ERT (Note 3).

[2] See “Exploration and Other” below for additional information related to the components of our exploration costs, including impairment charges for expiring unproved leases.

[3] Includes $138.6 million recorded to reduce our carrying value of ERT to its estimated fair value less costs to sell.

[4] Net interest expense of $27.7 million, $25.2 million and $19.7 million for the years ended December 31, 2012, 2011 and 2010, respectively, was allocated to ERT primarily based on interest associated with indebtedness directly attributed to the substantial acquisition made by our oil and gas subsidiary in 2006. This includes interest related to debt required to be paid upon the disposition of ERT.