Derivative Instruments - Derivatives Designated as Hedging Instruments by Classification and Amount of Gains and Losses (Detail) - Foreign currency forward exchange contracts - Designated As Hedging Instrument - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Nonoperating Income (Expense)
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gains (losses) recognized in OCI	$ 24,082	$ (55,377)	$ 18,733
Reclassification out of Accumulated Other Comprehensive Income | Derivative Instruments | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ (8,427)	$ (16,810)	$ 16,627