Derivative Financial Instruments - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Net gain (loss) on derivative financial instruments	$ (72,083,000)	$ (82,837,000)
Net deferred losses expected to be reclassified from AOCI over next 12 months	$ (55,300,000)
Derivative contracts, maturity date	Dec. 31, 2017
Fair value of derivative contracts	$ 45,453,000	$ 46,912,000
EPCI projects [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Notional value of outstanding derivative contracts	417,600,000
Foreign Exchange Forward
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Notional value of outstanding derivative contracts	$ 661,000,000