Operations by Business Segment and Geographic Area - Financial Data By Business Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenue	$ 2,271,603	$ 3,062,754	$ 3,659,624
Income from Operations	70,764	373,810	628,330
Depreciation, Depletion and Amortization, Nonproduction	250,247	241,235	229,779
Oil And Gas [Member]
Segment Reporting Information [Line Items]
Revenue	1,962,527	2,744,878	3,396,577
Income from Operations	143,158	478,368	765,110
Depreciation, Depletion and Amortization, Nonproduction	243,104	233,732	223,112
ROVs [Member]
Segment Reporting Information [Line Items]
Revenue	522,121	807,723	1,069,022
Income from Operations	25,193	192,514	320,550
Depreciation, Depletion and Amortization, Nonproduction	140,967	143,364	145,691
Subsea Products [Member]
Segment Reporting Information [Line Items]
Revenue	692,030	959,714	1,238,746
Income from Operations	75,938	175,585	281,239
Depreciation, Depletion and Amortization, Nonproduction	53,759	49,792	46,085
Subsea Projects [Member]
Segment Reporting Information [Line Items]
Revenue	472,979	604,484	588,572
Income from Operations	34,476	92,034	107,852
Depreciation, Depletion and Amortization, Nonproduction	34,042	29,863	18,561
Asset Integrity [Member]
Segment Reporting Information [Line Items]
Revenue	275,397	372,957	500,237
Income from Operations	7,551	18,235	55,469
Depreciation, Depletion and Amortization, Nonproduction	14,336	10,713	12,775
Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Revenue	309,076	317,876	263,047
Income from Operations	11,809	9,689	13,230
Depreciation, Depletion and Amortization, Nonproduction	3,120	2,549	2,574
Unallocated Expenses [Member]
Segment Reporting Information [Line Items]
Income from Operations	(84,203)	(114,247)	(150,010)
Depreciation, Depletion and Amortization, Nonproduction	$ 4,023	$ 4,954	$ 4,093