Summary Of Major Accounting Policies Long-lived asset impairments (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)
Impaired Long-Lived Assets Held and Used [Line Items]
Write-off Equipment and Intangibles			$ 7,300,000
Impairment property plant equipment		$ 51,578,000
Intangible Assets Impairments		477,000
Right-of-use asset impairment		16,708,000
Impairment of Long-Lived Assets Held-for-use	$ 0	$ 68,763,000		$ 0
Weighted Average [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Alternative Investment, Measurement Input		0.12
weighted average member low range [Member] [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Alternative Investment, Measurement Input		0.15
Measurement Input, Long-term Revenue Growth Rate [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Alternative Investment, Measurement Input		0.02
Oceaneering AGV System [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment property plant equipment		$ 145,000
Intangible Assets Impairments		310,000
Right-of-use asset impairment		695,000
Impairment of Long-Lived Assets Held-for-use		1,150,000
Oceaneering Entertainment System [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment property plant equipment		1,593,000
Right-of-use asset impairment		3,472,000
Impairment of Long-Lived Assets Held-for-use		5,065,000
Global Data Solution [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Intangible Assets Impairments		167,000
Impairment of Long-Lived Assets Held-for-use		167,000
Ecosse [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment property plant equipment		3,628,000
Intangible Assets Impairments		0
Right-of-use asset impairment			0
Impairment of Long-Lived Assets Held-for-use		3,628,000
Shallow Water [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment property plant equipment		3,894,000
Intangible Assets Impairments		0
Right-of-use asset impairment			$ 0
Impairment of Long-Lived Assets Held-for-use		3,894,000
Subsea Products Angola [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment property plant equipment		25,941,000
Right-of-use asset impairment		12,541,000
Impairment of Long-Lived Assets Held-for-use		38,482,000
SDS Brazil [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment property plant equipment		9,834,000
Impairment of Long-Lived Assets Held-for-use		9,834,000
SDS Rosyth [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment property plant equipment		6,543,000
Impairment of Long-Lived Assets Held-for-use		$ 6,543,000