Business Segment Information - Summary of Financial Data by Segment (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended								12 Months Ended
	Jan. 31, 2014	Jul. 31, 2013	Jun. 30, 2013	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net revenues				$ 157,683	$ 182,462	$ 166,016	$ 189,641	$ 207,160	$ 340,837	$ 305,587	$ 253,572	$ 695,802	$ 1,107,156	$ 876,561
Income (loss) from operations												(307,360)	261,756	179,034
Net interest expense												26,914	17,859	32,898
Equity in earnings (losses) of investments												(124,345)	879	2,965
Income (loss) before income taxes												(478,170)	262,521	143,588
Income tax provision (benefit)												(101,190)	66,971	31,612
Identifiable assets				2,411,952				2,700,698				2,411,952	2,700,698	2,544,280
Capital expenditures												320,311	336,912	324,426
Depreciation and amortization												120,401	109,345	98,535
Impairment charges												345,010	0	0
Goodwill impairment												16,399	0	0
Gain (loss) on sale of assets												92	10,240	14,727
Other income												4,759	16,931	6,581
Proceeds from insurance reimbursement													7,200
Loss on early extinguishment of debt												0	0	12,100
Unrealized losses on derivatives				19,000								18,281	1,320	77
Helix 534 [Member]
Segment Reporting Information [Line Items]
Impairment charges				205,200								205,200
Capitalized Vessel Project Costs [Member]
Segment Reporting Information [Line Items]
Impairment charges to write off capitalized costs				6,300								6,300
HP I [Member]
Segment Reporting Information [Line Items]
Impairment charges				133,400								133,400
Well Intervention [Member]
Segment Reporting Information [Line Items]
Goodwill impairment				16,400								16,399
Well Intervention [Member] | Helix 534 [Member]
Segment Reporting Information [Line Items]
Impairment charges												205,200
Well Intervention [Member] | Capitalized Vessel Project Costs [Member]
Segment Reporting Information [Line Items]
Impairment charges to write off capitalized costs												6,300
Robotics [Member]
Segment Reporting Information [Line Items]
Goodwill impairment													0
Unrealized losses on derivatives												18,300
Production Facilities [Member] | HP I [Member]
Segment Reporting Information [Line Items]
Impairment charges												133,400
Reportable Segments [Member] | Well Intervention [Member]
Segment Reporting Information [Line Items]
Net revenues												373,301	667,849	452,452
Income (loss) from operations												(194,381)	204,810	131,840
Net interest expense												(102)	(252)	(128)
Income (loss) before income taxes												(193,572)	211,725	132,057
Income tax provision (benefit)												(1,230)	50,102	26,718
Identifiable assets				1,492,901				1,470,349				1,492,901	1,470,349	1,245,229
Capital expenditures												307,879	283,635	283,132
Depreciation and amortization												66,095	57,570	44,619
Reportable Segments [Member] | Robotics [Member]
Segment Reporting Information [Line Items]
Net revenues												301,026	420,224	333,246
Income (loss) from operations												27,832	68,329	44,132
Net interest expense												29	(5)	19
Income (loss) before income taxes												2,454	61,025	44,342
Income tax provision (benefit)												515	21,612	15,530
Identifiable assets				274,926				299,701				274,926	299,701	282,373
Capital expenditures												10,700	51,348	39,655
Depreciation and amortization												26,724	24,478	22,263
Reportable Segments [Member] | Production Facilities [Member]
Segment Reporting Information [Line Items]
Net revenues												75,948	93,175	88,149
Income (loss) from operations												(106,847)	41,138	49,778
Net interest expense												385	384	380
Income (loss) before income taxes												(231,577)	41,633	52,363
Income tax provision (benefit)												(81,052)	14,395	17,233
Identifiable assets				182,007				459,427				182,007	459,427	495,829
Capital expenditures												1,867	869	1,252
Depreciation and amortization												21,340	21,278	17,193
Reportable Segments [Member] | Subsea Construction [Member]
Segment Reporting Information [Line Items]
Net revenues												0	358	71,321
Income (loss) from operations												(52)	10,923	33,685
Income (loss) before income taxes												53	11,201	33,205
Income tax provision (benefit)												26	3,881	11,655
Identifiable assets				10,027				27,547				10,027	27,547	38,054
Depreciation and amortization												0	0	8,651
Reportable Segments [Member] | Subsea Construction [Member] | Spoolbase Facility [Member]
Segment Reporting Information [Line Items]
Gain (loss) on sale of assets	$ 10,500
Reportable Segments [Member] | Subsea Construction [Member] | Caesar [Member]
Segment Reporting Information [Line Items]
Gain (loss) on sale of assets			$ (1,100)
Reportable Segments [Member] | Subsea Construction [Member] | Express [Member]
Segment Reporting Information [Line Items]
Gain (loss) on sale of assets		$ 15,600
Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Net revenues												(54,473)	(74,450)	(68,607)
Income (loss) from operations												(98)	(921)	(3,360)
Intercompany Elimination [Member] | Well Intervention [Member]
Segment Reporting Information [Line Items]
Net revenues												(22,855)	(29,875)	(22,448)
Intercompany Elimination [Member] | Robotics [Member]
Segment Reporting Information [Line Items]
Net revenues												(31,618)	(44,575)	(41,169)
Intercompany Elimination [Member] | Production Facilities [Member]
Segment Reporting Information [Line Items]
Net revenues												0	0	(4,673)
Intercompany Elimination [Member] | Subsea Construction [Member]
Segment Reporting Information [Line Items]
Net revenues												0	0	(317)
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations												(33,814)	(62,523)	(77,041)
Identifiable assets				$ 452,091				$ 443,674				452,091	443,674	482,795
Capital expenditures												(135)	1,060	387
Corporate and Eliminations [Member]
Segment Reporting Information [Line Items]
Net interest expense												26,602	17,732	32,627
Income (loss) before income taxes												(55,528)	(63,063)	(118,379)
Income tax provision (benefit)												(19,449)	(23,019)	(39,524)
Depreciation and amortization												$ 6,242	6,019	5,809
Other income													16,900
Proceeds from insurance reimbursement													$ 7,200
Loss on early extinguishment of debt														$ 12,100