Operations by Business Segment and Geographic Area - Financial Data By Business Segment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Goodwill, Impairment Loss	$ 76,449	$ 0	$ 0
Revenue	1,909,482	1,921,507	2,271,603
Income from Operations	(145,482)	10,656	70,764
Depreciation, Depletion and Amortization, Nonproduction	293,590	213,519	250,247
Restructuring Charges			11,600
Oil And Gas [Member]
Segment Reporting Information [Line Items]
Revenue	1,492,850	1,547,939	1,962,527
Income from Operations	(70,093)	89,415	143,158
Depreciation, Depletion and Amortization, Nonproduction	285,781	206,124	243,104
ROVs [Member]
Segment Reporting Information [Line Items]
Revenue	394,801	393,655	522,121
Income from Operations	1,641	22,366	25,193
Depreciation, Depletion and Amortization, Nonproduction	111,311	113,979	140,967
Subsea Products [Member]
Segment Reporting Information [Line Items]
Revenue	515,000	625,513	692,030
Income from Operations	5,614	45,539	75,938
Depreciation, Depletion and Amortization, Nonproduction	53,085	52,561	53,759
Subsea Projects [Member]
Segment Reporting Information [Line Items]
Revenue	329,163	291,993	472,979
Income from Operations	(86,008)	10,279	34,476
Depreciation, Depletion and Amortization, Nonproduction	114,481	31,869	34,042
Asset Integrity [Member]
Segment Reporting Information [Line Items]
Revenue	253,886	236,778	275,397
Income from Operations	8,660	11,231	7,551
Depreciation, Depletion and Amortization, Nonproduction	6,904	7,715	14,336
Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Revenue	416,632	373,568	309,076
Income from Operations	33,920	22,039	11,809
Depreciation, Depletion and Amortization, Nonproduction	3,081	3,171	3,120
Unallocated Expenses [Member]
Segment Reporting Information [Line Items]
Income from Operations	(109,309)	(100,798)	(84,203)
Depreciation, Depletion and Amortization, Nonproduction	$ 4,728	$ 4,224	$ 4,023

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

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