Business Segment Information (Summary Of Financial Data By Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Segment Reporting Information [Line Items]
Revenues	$ 305,587		$ 232,178		$ 559,159		$ 429,607
Income (loss) from operations	78,756		47,197		145,704		62,435
Equity in earnings (losses) of investments	(507)		683		201		1,293
Gain (loss) on disposition of assets, net	(1,078)		(1,085)		10,418		(1,085)
Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues	(19,384)		(17,352)		(36,900)		(38,370)
Income (loss) from operations	45		(839)		(1,153)		(2,559)
Well Intervention [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	181,218		99,323		340,918		205,655
Income (loss) from operations	64,775		23,912		113,508		60,362
Well Intervention [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues	(7,956)		(6,439)		(13,417)		(10,268)
Robotics [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	119,704		88,374		207,594		152,570
Income (loss) from operations	20,799		13,296		32,018		12,599
Robotics [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues	(11,428)		(10,913)		(23,483)		(23,112)
Subsea Construction [Member]
Segment Reporting Information [Line Items]
Gain (loss) on disposition of assets, net					10,500
Subsea Construction [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues			37,659		358		65,185
Income (loss) from operations	145	[1]	10,392	[1]	10,830	[1]	13,943	[1]
Subsea Construction [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues							(317)
Production Facilities [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	24,049		24,174		47,189		44,567
Income (loss) from operations	10,459		14,643		21,843		25,828
Production Facilities [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues							(4,673)
Corporate and Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	$ (17,467)		$ (14,207)		$ (31,342)		$ (47,738)

[1] Amount in 2014 includes the $10.5 million gain on the sale in January 2014 of our Ingleside spoolbase.