Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 416,413	$ 484,175	$ 446,176
Rovs Member
Segment Reporting Information [Line Items]
Revenues	85,594	91,584	94,022
Subsea Products Member
Segment Reporting Information [Line Items]
Revenues	126,688	156,398	150,639
Subsea Projects Member
Segment Reporting Information [Line Items]
Revenues	56,860	73,376	62,956
Asset Integrity [Member]
Segment Reporting Information [Line Items]
Revenues	61,288	64,830	52,658
Oil And Gas [Member]
Segment Reporting Information [Line Items]
Revenues	330,430	386,188	360,275
Advanced Technologies Member
Segment Reporting Information [Line Items]
Revenues	$ 85,983	$ 97,987	$ 85,901