Derivatives and Hedge Accounting - Summary of Effect of Foreign Currency Exchange Contracts on Consolidated Statements of Income (Detail) - Foreign Currency Exchange Contracts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivatives Designated as Hedging Instruments | Derivatives in Cash Flow Hedging Relationships
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in AOCI on Derivative (Effective Portion)	$ (1,111)	$ 6,770
Foreign exchange gain/(loss) | Derivatives Designated as Hedging Instruments | Derivatives in Cash Flow Hedging Relationships
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Loss Reclassified from AOCI into Income (Effective Portion)	(1,117)	(7,140)
Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)	0	0
Foreign exchange gain/(loss) | Derivatives not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in Income on Derivatives	$ 862	$ 3,685