Business Segment Information (Summary Of Financial Data By Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Net revenues	$ 182,462	$ 340,837	$ 538,119	$ 899,996
Income (loss) from operations	18,372	106,331	48,374	252,035
Equity in earnings (losses) of investments	(251)	508	(553)	709
Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Net revenues	(14,876)	(20,193)	(42,895)	(57,093)
Income (loss) from operations	(163)	103	(256)	(1,050)
Well Intervention [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net revenues	94,895	205,139	284,621	546,057
Income (loss) from operations	6,233	80,789	25,162	194,297
Well Intervention [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Net revenues	(7,324)	(8,635)	(18,687)	(22,052)
Robotics [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net revenues	83,310	131,707	238,582	339,301
Income (loss) from operations	14,329	28,397	28,089	60,415
Robotics [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Net revenues	(7,552)	(11,558)	(24,208)	(35,041)
Production Facilities [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net revenues	19,133	24,184	57,811	71,373
Income (loss) from operations	6,938	11,284	19,960	33,127
Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net revenues	0	0	0	358
Corporate and Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	$ (8,965)	$ (14,242)	$ (24,581)	$ (34,754)