Business Segment Information - Financial Data By Business Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Segment Reporting Information [Line Items]
Revenue	$ 608,344	$ 722,066	$ 786,772
Income from Operations	48,099	45,756	106,650
Depreciation and amortization	59,781	57,727	58,003
Oil And Gas [Member]
Segment Reporting Information [Line Items]
Revenue	541,455	647,056	712,241
Income from Operations	74,850	64,222	139,497
Depreciation and amortization	57,923	55,884	56,063
ROVs [Member]
Segment Reporting Information [Line Items]
Revenue	147,621	173,424	219,447
Income from Operations	26,987	16,621	62,182
Depreciation and amortization	33,684	36,222	36,481
Subsea Products [Member]
Segment Reporting Information [Line Items]
Revenue	194,812	258,889	240,729
Income from Operations	40,640	37,206	50,014
Depreciation and amortization	12,807	11,428	12,068
Subsea Projects [Member]
Segment Reporting Information [Line Items]
Revenue	129,422	131,397	153,572
Income from Operations	6,789	10,310	22,276
Depreciation and amortization	8,519	5,533	4,651
Asset Integrity [Member]
Segment Reporting Information [Line Items]
Revenue	69,600	83,346	98,493
Income from Operations	434	85	5,025
Depreciation and amortization	2,913	2,701	2,863
Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Revenue	66,889	75,010	74,531
Income from Operations	593	(3,233)	5,020
Depreciation and amortization	734	670	642
Unallocated Expenses [Member]
Segment Reporting Information [Line Items]
Income from Operations	(27,344)	(15,233)	(37,867)
Depreciation and amortization	$ 1,124	$ 1,173	$ 1,298