Business Segment Information - Total Assets By Reportable Segment (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 2,505,474	$ 2,596,731
Corporate and Other
Segment Reporting Information [Line Items]
Total assets	118,269	122,449
Well Intervention | Reportable Segments
Segment Reporting Information [Line Items]
Total assets	2,110,889	2,180,180
Robotics | Reportable Segments
Segment Reporting Information [Line Items]
Total assets	142,538	151,478
Production Facilities | Reportable Segments
Segment Reporting Information [Line Items]
Total assets	$ 133,778	$ 142,624