Business Segment Information (Intercompany Segment Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Assets	$ 2,934,196	$ 2,700,698
Well Intervention [Member]
Segment Reporting Information [Line Items]
Assets	1,805,388	1,470,349
Robotics [Member]
Segment Reporting Information [Line Items]
Assets	304,357	299,701
Production Facilities [Member]
Segment Reporting Information [Line Items]
Assets	446,199	459,427
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Assets	$ 378,252	$ 471,221