Derivative Financial Instruments - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Net gain (loss) on derivative financial instruments	$ (28,844,000)	$ (64,277,000)
Net deferred losses expected to be reclassified from AOCI over next 12 months	18,000,000
Notional value of outstanding derivative contracts	$ 357,000,000
Derivative contracts, maturity date	Dec. 31, 2017
Fair value of derivative contracts	$ 8,000,000
EPCI projects [Member]
Derivative [Line Items]
Notional value of outstanding derivative contracts	$ 214,000,000