Business Segment Information (Intercompany Segment Gross Profit (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Gross profit	$ (32,805)	$ (126,247)	$ (109,138)	$ (75,846)	$ (71,164)	$ (69,457)	$ (67,497)	$ (52,567)	$ (344,036)	$ (260,685)	$ (49,915)
Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit (loss) with other operating segments of same entity									921	3,360	7,878
Well Intervention [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit (loss) with other operating segments of same entity									(323)	(141)	6,203
Robotics [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit (loss) with other operating segments of same entity									1,419	3,518	180
Production Facilities [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit (loss) with other operating segments of same entity									(175)	(175)	(175)
Subsea Construction [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Gross profit (loss) with other operating segments of same entity										$ 158	$ 1,670