Business Segment Information - Total Assets By Reportable Segment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total assets	$ 2,347,299	$ 2,498,278
Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Total assets	74,411	101,874
Well Intervention | Reportable Segments
Segment Reporting Information [Line Items]
Total assets	2,042,180	2,134,081
Robotics | Reportable Segments
Segment Reporting Information [Line Items]
Total assets	109,450	132,550
Production Facilities | Reportable Segments
Segment Reporting Information [Line Items]
Total assets	$ 121,258	$ 129,773