Supplemental Oil And Gas Disclosures (Capitalized Costs) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Capitalized Costs Relating to Oil and Gas Producing Activities, by Geographic Area [Line Items]
Asset retirement obligation	$ 200,978	$ 227,090	$ 222,653
Oil and Gas Properties [Member]
Capitalized Costs Relating to Oil and Gas Producing Activities, by Geographic Area [Line Items]
Asset retirement obligation	203,900	254,400
Helix [Member]
Capitalized Costs Relating to Oil and Gas Producing Activities, by Geographic Area [Line Items]
Unproved oil and gas properties	51,513	50,389
Proved oil and gas properties	2,453,667	2,516,363
Total oil and gas properties	2,505,180	2,566,752
Accumulated depletion, depreciation and amortization	(1,717,314)	(1,695,105)
Net capitalized costs	$ 787,866	$ 871,647