Use of Estimates - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($) Project	Sep. 30, 2015 USD ($) Project	Sep. 30, 2014 USD ($)
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	$ 8.0		$ 21.0
AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	11.0	$ 1.5	1.0	$ (41.5)
Number of projects | Project		5
MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	6.0	$ 5.4	$ 16.0	10.7
Number of projects | Project			3
MEA [Member] | Project One [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	6.0
MEA [Member] | Project Two
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	3.0
ASA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	3.0	$ 20.2	$ 6.0	10.3
Number of projects | Project		3
Marine Campaign Execution Plan And Legal Charges | AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	6.0
PB Litoral project [Member] | AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	13.0	$ 10.9	13.0	66.3
U.A.E. project [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	4.0		9.0
Multiple projects [Member] | AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results		4.8	1.0
Multiple projects [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	(1.0)
Partial offset on estimated costs on project			2.0
Multiple projects [Member] | ASA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	5.0	9.5	10.0
Brunei Project [Member] | ASA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	$ 8.0	10.8	8.0	11.8
Agile Charter [Member] | AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results			4.0
Papa Terra Project | AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results			3.0	(37.4)
North Ocean one hundred and five demobilization [Member] | AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results			6.0
Intermac cable lay project | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results			11.0
Cable Lay Scope [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results			5.0
U.A.E. project two [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results			5.0
Marine Hook-up Campaign Savings Karan 45 [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results			4.0
KJO Hout Project [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results			7.0
EPCI project two Saudi Arabia [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results		6.7	(5.0)
Gorgon MRU Fabrication Project [Member] | ASA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results			$ 4.0
Jack & St. Malo [Member] | AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results		(12.4)		10.1
Morgan City Fabrication Project [Member] | AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results		4.8		7.8
EPCI project one Saudi Arabia [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results		7.9
EPCI projects Saudi Arabia [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results		8.6		15.2
EPCI projects Saudi Arabia [Member] | MEA [Member] | Project Two
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results				42.4
Caspian Pipelay project [Member] | MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results		$ 17.8		46.9
Marine Installation Project [Member] | AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results				5.2
Siakap [Member] | ASA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results				53.5
Siakap project [Member] | ASA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results				$ 31.5