Business Segment Information - Total Assets By Reportable Segment (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total assets	$ 2,432,290	$ 2,246,941
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Total assets	430,814	305,331
Well Intervention [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total assets	1,678,774	1,596,517
Robotics [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total assets	167,949	186,901
Production Facilities [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total assets	$ 154,753	$ 158,192