Business Segment Information - Financial Data By Business Segment (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)			$ 7,600
Revenue	$ 497,647	$ 495,781	519,300	$ 1,487,314	$ 1,414,387
Income (Loss) from Operations	(5,194)	(9,635)	(1,552)	(36,543)	(48,338)
Depreciation and amortization	50,567	50,304	50,703	153,357	164,674
Oil and Gas [Member]
Segment Reporting Information [Line Items]
Revenue	399,207	395,533	409,462	1,174,347	1,114,480
Income (Loss) from Operations	20,295	14,886	14,502	38,302	13,015
Depreciation and amortization	48,586	48,357	48,876	147,440	158,776
Remotely Operated Vehicles [Member]
Segment Reporting Information [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)			600
Revenue	113,101	120,363	105,045	333,810	298,065
Income (Loss) from Operations	10,145	8,688	772	20,251	2,916
Depreciation and amortization	26,767	26,871	27,428	81,628	83,339
Subsea Products [Member]
Segment Reporting Information [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)			1,500
Revenue	150,836	138,910	137,099	418,590	385,491
Income (Loss) from Operations	13,219	7,413	5,367	20,156	9,417
Depreciation and amortization	12,055	12,366	12,349	37,412	41,288
Subsea Projects [Member]
Segment Reporting Information [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)			5,500
Revenue	75,996	75,104	104,972	240,828	239,868
Income (Loss) from Operations	(616)	87	6,088	2,363	(6,629)
Depreciation and amortization	8,130	7,550	7,464	23,562	28,830
Asset Integrity [Member]
Segment Reporting Information [Line Items]
Revenue	59,274	61,156	62,346	181,119	191,056
Income (Loss) from Operations	(2,453)	(1,302)	2,275	(4,468)	7,311
Depreciation and amortization	1,634	1,570	1,635	4,838	5,319
Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Revenue	98,440	100,248	109,838	312,967	299,907
Income (Loss) from Operations	2,958	7,241	8,960	19,798	18,514
Depreciation and amortization	761	765	792	2,356	2,295
Unallocated Expenses [Member]
Segment Reporting Information [Line Items]
Income (Loss) from Operations	(28,447)	(31,762)	(25,014)	(94,643)	(79,867)
Depreciation and amortization	$ 1,220	$ 1,182	$ 1,035	$ 3,561	$ 3,603

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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