Revenue From Contracts With Customers - Schedule Of Disaggregated Revenue (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Disaggregation of Revenue [Line Items]
Revenue	$ 164,262
Minimum contract duration to be classified as long-term	12 months
Well Intervention
Disaggregation of Revenue [Line Items]
Revenue	$ 129,569
Robotics
Disaggregation of Revenue [Line Items]
Revenue	27,169
Production Facilities
Disaggregation of Revenue [Line Items]
Revenue	16,321
Intercompany Elimination
Disaggregation of Revenue [Line Items]
Revenue	(8,797)
Short-term
Disaggregation of Revenue [Line Items]
Revenue	62,351
Short-term | Well Intervention
Disaggregation of Revenue [Line Items]
Revenue	42,027
Short-term | Robotics
Disaggregation of Revenue [Line Items]
Revenue	20,324
Short-term | Production Facilities
Disaggregation of Revenue [Line Items]
Revenue	0
Short-term | Intercompany Elimination
Disaggregation of Revenue [Line Items]
Revenue	0
Long-term
Disaggregation of Revenue [Line Items]
Revenue	101,911
Long-term | Well Intervention
Disaggregation of Revenue [Line Items]
Revenue	87,542
Long-term | Robotics
Disaggregation of Revenue [Line Items]
Revenue	6,845
Long-term | Production Facilities
Disaggregation of Revenue [Line Items]
Revenue	16,321
Long-term | Intercompany Elimination
Disaggregation of Revenue [Line Items]
Revenue	$ (8,797)