Operations by Business Segment and Geographic Area Operations by Business Segment and Geographic Area - Other Significant Reconciling Items (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Asset Reconciling Item [Line Items]
Property, Plant and Equipment, Additions	$ 426,671	$ 393,590	$ 309,858
Oil And Gas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, Plant and Equipment, Additions	420,644	377,698	300,825
ROVs [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, Plant and Equipment, Additions	188,848	225,885	198,323
Subsea Products [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, Plant and Equipment, Additions	112,851	102,653	68,052
Subsea Projects [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, Plant and Equipment, Additions	91,918	40,833	15,890
Asset Integrity [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, Plant and Equipment, Additions	27,027	8,327	18,560
Advanced Technologies [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, Plant and Equipment, Additions	2,352	13,175	2,953
Corporate and Other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, Plant and Equipment, Additions	$ 3,675	$ 2,717	$ 6,080