Business Segment Information (Summary Of Financial Data By Segment) (Details) (USD $)	3 Months Ended								12 Months Ended			1 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013	Jul. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 207,160,000	$ 340,837,000	$ 305,587,000	$ 253,572,000	$ 226,837,000	$ 220,117,000	$ 232,178,000	$ 197,429,000	$ 1,107,156,000	$ 876,561,000	$ 846,109,000
Income (loss) from operations									261,756,000	179,034,000	(68,483,000)
Net interest expense and other									114,000	38,411,000	65,949,000
Equity in earnings of investments									879,000	2,965,000	8,434,000
Income (loss) before income taxes									262,521,000	143,588,000	(125,998,000)
Provision for income taxes									66,971,000	31,612,000	(59,158,000)
Total assets	2,700,698,000				2,544,280,000				2,700,698,000	2,544,280,000	3,386,580,000
Capital expenditures									336,912,000	324,426,000	323,039,000
Depreciation and amortization									109,345,000	98,535,000	97,201,000
Gain (loss) on disposition of assets, net									10,240,000	14,727,000	(13,476,000)
Other income - oil and gas									16,931,000	6,581,000
Proceeds from insurance reimbursement									7,200,000
Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues									(74,450,000)	(68,607,000)	(133,775,000)
Well Intervention [Member]
Segment Reporting Information [Line Items]
Revenues									667,849,000	452,452,000	378,546,000
Income (loss) from operations									204,810,000	131,840,000	85,482,000
Net interest expense and other									(6,915,000)	(217,000)	2,152,000
Income (loss) before income taxes									211,725,000	132,057,000	83,205,000
Provision for income taxes									50,102,000	26,718,000	15,400,000
Total assets	1,470,349,000				1,245,229,000				1,470,349,000	1,245,229,000	936,926,000
Capital expenditures									283,635,000	283,132,000	274,451,000
Depreciation and amortization									57,570,000	44,619,000	37,736,000
Well Intervention [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues									(29,875,000)	(22,448,000)	(36,781,000)
Robotics [Member]
Segment Reporting Information [Line Items]
Revenues									420,224,000	333,246,000	328,726,000
Income (loss) from operations									68,329,000	44,132,000	55,678,000
Net interest expense and other									7,304,000	(210,000)	(1,203,000)
Income (loss) before income taxes									61,025,000	44,342,000	56,881,000
Provision for income taxes									21,612,000	15,530,000	20,222,000
Total assets	299,701,000				282,373,000				299,701,000	282,373,000	258,117,000
Capital expenditures									51,348,000	39,655,000	44,500,000
Depreciation and amortization									24,478,000	22,263,000	19,933,000
Robotics [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues									(44,575,000)	(41,169,000)	(46,465,000)
Production Facilities [Member]
Segment Reporting Information [Line Items]
Revenues									93,175,000	88,149,000	80,091,000
Income (loss) from operations									41,138,000	49,778,000	40,082,000
Net interest expense and other									384,000	380,000	365,000
Income (loss) before income taxes									41,633,000	52,363,000	48,276,000
Provision for income taxes									14,395,000	17,233,000	15,784,000
Total assets	459,427,000				495,829,000				459,427,000	495,829,000	504,828,000
Capital expenditures									869,000	1,252,000	823,000
Depreciation and amortization									21,278,000	17,193,000	16,828,000
Production Facilities [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues										(4,673,000)	(46,057,000)
Subsea Construction [Member]
Segment Reporting Information [Line Items]
Revenues									358,000	71,321,000	192,521,000
Income (loss) from operations									10,923,000	33,685,000	(148,862,000)
Net interest expense and other									(278,000)	480,000	(247,000)
Income (loss) before income taxes									11,201,000	33,205,000	(148,615,000)
Provision for income taxes									3,881,000	11,655,000	(51,329,000)
Total assets	27,547,000				38,054,000				27,547,000	38,054,000	303,479,000
Depreciation and amortization										8,651,000	19,773,000
Subsea Construction [Member] | Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues										(317,000)	(4,472,000)
Spoolbase Facility [Member]
Segment Reporting Information [Line Items]
Gain (loss) on disposition of assets, net									10,500,000
Caesar [Member]
Segment Reporting Information [Line Items]
Gain (loss) on disposition of assets, net												(1,100,000)
Asset impairment											157,800,000
Express [Member]
Segment Reporting Information [Line Items]
Gain (loss) on disposition of assets, net													15,600,000
Intrepid Vessel [Member]
Segment Reporting Information [Line Items]
Asset impairment											14,600,000
Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues									(74,450,000)	(68,607,000)	(133,775,000)
Income (loss) from operations									(921,000)	(3,360,000)	(7,878,000)
Corporate And Eliminations [Member]
Segment Reporting Information [Line Items]
Net interest expense and other									(381,000)	37,978,000	64,882,000
Income (loss) before income taxes									(63,063,000)	(118,379,000)	(165,745,000)
Provision for income taxes									(23,019,000)	(39,524,000)	(59,235,000)
Depreciation and amortization									6,019,000	5,809,000	2,931,000
Corporate [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									(62,523,000)	(77,041,000)	(92,985,000)
Total assets	443,674,000				482,795,000				443,674,000	482,795,000	483,003,000
Capital expenditures									1,060,000	387,000	3,265,000
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Total assets											$ 900,227,000