Organization (Details)	12 Months Ended
	Dec. 31, 2018 segment vessel	Jan. 18, 2019 well
Segment Reporting Information [Line Items]
Number of reportable segments | segment	3
Well Intervention
Segment Reporting Information [Line Items]
Number of chartered vessels	2
Robotics
Segment Reporting Information [Line Items]
Number of chartered vessels	3
Production Facilities | Droshky Prospect | Subsequent Event
Segment Reporting Information [Line Items]
Number of wells with production | well		2