Financial Derivatives and Hedging Activities - Fair Values of Derivative Instruments (Detail) - Forward Foreign Currency Exchange Contracts [Member] - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Designated as Hedging [Member] | Prepaid Expenses and Other Current Assets [Member]
Derivatives Fair Value [Line Items]
Derivative asset, fair value	$ 138	$ 1,066
Designated as Hedging [Member] | Other Current Liabilities [Member]
Derivatives Fair Value [Line Items]
Derivative liability, fair value	5,955	4,787
Not Designated as Hedging [Member] | Prepaid Expenses and Other Current Assets [Member]
Derivatives Fair Value [Line Items]
Derivative asset, fair value	276	151
Not Designated as Hedging [Member] | Other Current Liabilities [Member]
Derivatives Fair Value [Line Items]
Derivative liability, fair value	$ 147	$ 43