Business Segment Information - Intercompany Segment Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Net revenues	$ (163,415)	$ (181,021)
Well Intervention
Segment Reporting Information [Line Items]
Net revenues	(133,768)	(140,652)
Robotics
Segment Reporting Information [Line Items]
Net revenues	(22,156)	(35,258)
Intercompany Eliminations
Segment Reporting Information [Line Items]
Net revenues	8,956	10,430
Intercompany Eliminations | Well Intervention
Segment Reporting Information [Line Items]
Net revenues	2,587	3,304
Intercompany Eliminations | Robotics
Segment Reporting Information [Line Items]
Net revenues	$ 6,369	$ 7,126