Business Segment Information - Summary Of Financial Data By Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Net revenues	$ 204,625	$ 150,329	$ 368,887	$ 254,857
Income (loss) from operations	24,772	5,050	23,656	(12,655)
Corporate and Other
Segment Reporting Information [Line Items]
Income (loss) from operations	(12,684)	(8,701)	(20,940)	(18,663)
Intercompany Elimination
Segment Reporting Information [Line Items]
Net revenues	(12,537)	(11,018)	(21,334)	(19,454)
Income (loss) from operations	222	221	443	442
Well Intervention | Reportable Segments
Segment Reporting Information [Line Items]
Net revenues	161,759	113,076	291,328	187,697
Income (loss) from operations	34,470	19,032	48,347	20,450
Well Intervention | Intercompany Elimination
Segment Reporting Information [Line Items]
Net revenues	(4,215)	(2,895)	(6,167)	(4,268)
Robotics | Reportable Segments
Segment Reporting Information [Line Items]
Net revenues	39,060	33,061	66,229	55,029
Income (loss) from operations	(4,102)	(11,642)	(18,419)	(27,948)
Robotics | Intercompany Elimination
Segment Reporting Information [Line Items]
Net revenues	(8,322)	(8,123)	(15,167)	(15,186)
Production Facilities | Reportable Segments
Segment Reporting Information [Line Items]
Net revenues	16,343	15,210	32,664	31,585
Income (loss) from operations	$ 6,866	$ 6,140	$ 14,225	$ 13,064