Revenue - Performance obligation (Details) $ in Millions	Mar. 31, 2019 USD ($)
Revenue from Contract with Customer [Abstract]
Price allocated to remaining performance obligations	$ 364
Revenue recognition for remaining performance obligations	$ 272

Revenue to be recognized for the remaining performance obligations over next 12 months

No definition available.

Name:	oii_RevenueRecognitionforRemainingPerformanceObligations
Namespace Prefix:	oii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant