Business Segment Information (Intercompany Segment Gross Profit (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Gross profit	$ 69,457	$ 57,919	$ 189,521	$ 158,840
Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit	21	39	(2,538)	(2,883)
Well Intervention [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit	45	57	91	(1,259)
Robotics [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit	(67)	(62)	(2,602)	(98)
Subsea Construction [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit			(158)	(1,657)
Production Facilities [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit	$ 43	$ 44	$ 131	$ 131