Operations by Business Segment and Geographic Area - Financial Data By Business Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenue	$ 3,062,754	$ 3,659,624	$ 3,287,019
Income from Operations	373,810	628,330	545,116
Depreciation, Depletion and Amortization, Nonproduction	241,235	229,779	202,228
Oil And Gas [Member]
Segment Reporting Information [Line Items]
Revenue	2,744,878	3,396,577	3,000,879
Income from Operations	478,368	765,110	662,131
Depreciation, Depletion and Amortization, Nonproduction	233,732	223,112	196,006
ROVs [Member]
Segment Reporting Information [Line Items]
Revenue	807,723	1,069,022	981,728
Income from Operations	192,514	320,550	281,973
Depreciation, Depletion and Amortization, Nonproduction	143,364	145,691	128,310
Subsea Products [Member]
Segment Reporting Information [Line Items]
Revenue	959,714	1,238,746	1,027,792
Income from Operations	175,585	281,239	231,050
Depreciation, Depletion and Amortization, Nonproduction	49,792	46,085	39,964
Subsea Projects [Member]
Segment Reporting Information [Line Items]
Revenue	604,484	588,572	509,440
Income from Operations	92,034	107,852	93,865
Depreciation, Depletion and Amortization, Nonproduction	29,863	18,561	15,331
Asset Integrity [Member]
Segment Reporting Information [Line Items]
Revenue	372,957	500,237	481,919
Income from Operations	18,235	55,469	55,243
Depreciation, Depletion and Amortization, Nonproduction	10,713	12,775	12,401
Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Revenue	317,876	263,047	286,140
Income from Operations	9,689	13,230	24,954
Depreciation, Depletion and Amortization, Nonproduction	2,549	2,574	2,682
Unallocated Expenses [Member]
Segment Reporting Information [Line Items]
Income from Operations	(114,247)	(150,010)	(141,969)
Depreciation, Depletion and Amortization, Nonproduction	$ 4,954	$ 4,093	$ 3,540