Derivative Financial Instruments - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Net gain (loss) on derivative financial instruments	$ (72,784,000)	$ (82,837,000)
Net deferred losses expected to be reclassified from AOCI over next 12 months	$ (55,600,000)
Derivative contracts, maturity date	Dec. 31, 2017
Fair value of derivative contracts	$ 47,230,000
EPCI projects [Member]
Derivative [Line Items]
Notional value of outstanding derivative contracts	447,000,000
Foreign Exchange Forward
Derivative [Line Items]
Notional value of outstanding derivative contracts	$ 673,100,000