Summary Of Major Accounting Policies - Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Remotely Operated Vehicles [Member] Y	Dec. 31, 2011 Marine Services Equipment [Member] Y	Dec. 31, 2011 Building and Building Improvements [Member] Y	Dec. 31, 2011 Maximum [Member]	Dec. 31, 2009 Maximum [Member]
Property, Plant and Equipment [Line Items]
Cash and Cash Equivalents, Short-term Investments, Maturity Period						3 months
Property, Plant and Equipment, Useful Life, Average			8
Property, Plant and Equipment, Useful Life, Maximum				20	25
Property, Plant and Equipment, Useful Life, Minimum				3	3
Interest Costs, Capitalized, Minimum Construction Period	3 months
Interest Costs, Capitalized During Period	$ 0	$ 0.3					$ 0.1
Asset Impairment Charges		$ 5.2