Derivative Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Net gain (loss) on derivative financial instruments	$ (33,473,000)	$ (64,277,000)
Net deferred losses expected to be reclassified from AOCI over next 12 months	24,000,000
Notional value of outstanding derivative contracts	$ 536,000,000
Derivative contracts, maturity date	Dec. 31, 2017
Fair value of derivative contracts	$ 3,000,000
EPCI projects [Member]
Derivative [Line Items]
Notional value of outstanding derivative contracts	$ 286,000,000