Company Overview (Details)		9 Months Ended
	Feb. 01, 2017	Sep. 30, 2017 segment vessel
Segment Reporting Information [Line Items]
Number of reportable segments | segment		3
Well Intervention [Member]
Segment Reporting Information [Line Items]
Number of chartered vessels		2
Robotics [Member]
Segment Reporting Information [Line Items]
Number of chartered vessels		4
HFRS [Member] | Production Facilities [Member]
Segment Reporting Information [Line Items]
Contract extension period	1 year