Business Segment Information - Summary Of Intercompany Segment Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Net revenues	$ (163,260)	$ (161,245)	$ (418,117)	$ (359,551)
Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Net revenues	11,691	13,067	31,145	29,083
Intercompany Elimination [Member] | Well Intervention [Member]
Segment Reporting Information [Line Items]
Net revenues	3,765	2,898	8,033	5,740
Intercompany Elimination [Member] | Robotics [Member]
Segment Reporting Information [Line Items]
Net revenues	$ 7,926	$ 10,169	$ 23,112	$ 23,343