Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 493,886	$ 495,095	$ 416,413	$ 495,095
Remotely Operated Vehicles [Member]
Segment Reporting Information [Line Items]
Revenues	100,346	96,736	85,594
Subsea Products [Member]
Segment Reporting Information [Line Items]
Revenues	128,844	129,509	126,688
Subsea Projects [Member]
Segment Reporting Information [Line Items]
Revenues	89,728	89,295	56,860
Asset Integrity [Member]
Segment Reporting Information [Line Items]
Revenues	60,689	62,830	61,288
Oil and Gas [Member]
Segment Reporting Information [Line Items]
Revenues	379,607	378,370	330,430
Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Revenues	$ 114,279	$ 116,725	$ 85,983