Business Segment Information - Financial Data By Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net revenues	$ 166,823	$ 164,262
Income (loss) from operations	269	(1,116)
Reportable Segments
Segment Reporting Information [Line Items]
Income (loss) from operations	10,142	6,919
Intercompany Eliminations
Segment Reporting Information [Line Items]
Net revenues	(9,702)	(8,797)
Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Income (loss) from operations	(9,873)	(8,035)
Well Intervention
Segment Reporting Information [Line Items]
Net revenues	122,231	129,569
Well Intervention | Reportable Segments
Segment Reporting Information [Line Items]
Net revenues	122,231	129,569
Income (loss) from operations	9,641	13,877
Well Intervention | Intercompany Eliminations
Segment Reporting Information [Line Items]
Net revenues	(3,225)	(1,952)
Robotics
Segment Reporting Information [Line Items]
Net revenues	39,041	27,169
Robotics | Reportable Segments
Segment Reporting Information [Line Items]
Net revenues	39,041	27,169
Income (loss) from operations	(3,904)	(14,317)
Robotics | Intercompany Eliminations
Segment Reporting Information [Line Items]
Net revenues	(6,477)	(6,845)
Production Facilities
Segment Reporting Information [Line Items]
Net revenues	15,253	16,321
Production Facilities | Reportable Segments
Segment Reporting Information [Line Items]
Net revenues	15,253	16,321
Income (loss) from operations	$ 4,405	$ 7,359