Operations by Business Segment and Geographic Area - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Equity Method Investment, Significant Property, Plant and Equipment Owned by Equity Method Investee		75.00%
Gain (Loss) on Sale of Property Plant Equipment	$ 584,000	$ 24,188,000	$ 2,758,000
Impairment charge on vessel held for sale			5,200,000
Medusa Spar LLC Investment [Member]
Segment Reporting Information [Line Items]
Equity Method Investment, Ownership Percentage	50.00%	50.00%
Equity Method Investment, Significant Property, Plant and Equipment Owned by Equity Method Investee	75.00%
Sales [Member] | Customer Concentration Risk [Member]
Segment Reporting Information [Line Items]
Major Customer Above Benchmark Threshold, Number	1	0	1
BP [Member] | Sales [Member] | Customer Concentration Risk [Member]
Segment Reporting Information [Line Items]
Concentration Risk, Percentage	13.00%		12.00%
Subsea Projects Member
Segment Reporting Information [Line Items]
Gain (Loss) on Sale of Property Plant Equipment		$ 19,600,000