Summary Of Significant Accounting Policies (Summary Of Gross Components Of Property And Equipment) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 4,391,064	$ 4,486,077
ROVs/Vessels [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	1,616,772	1,573,471
Estimated Useful Life, Minimum in years	10
Estimated Useful Life, Maximum in years	30
Oil And Gas Leases And Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	2,574,693	2,747,895
Machinery, Equipment, Buildings And Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 199,599	$ 164,711
Estimated Useful Life, Minimum in years	5
Estimated Useful Life, Maximum in years	30