Derivative Instruments and Hedging Activities - Carrying Values of Derivative Instruments (Detail) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Net Carrying Value		$ (426)	$ 298
Designated as Hedging Instrument
Derivative [Line Items]
Derivative Net Carrying Value		(426)	298
Designated as Hedging Instrument | Foreign currency contracts
Derivative [Line Items]
Derivative Net Carrying Value	[1]	(426)	298
Prepaid Expenses And Other Current Assets
Derivative [Line Items]
Fair Value— Assets		621	2,128
Prepaid Expenses And Other Current Assets | Designated as Hedging Instrument
Derivative [Line Items]
Fair Value— Assets		621	2,128
Prepaid Expenses And Other Current Assets | Designated as Hedging Instrument | Foreign currency contracts
Derivative [Line Items]
Fair Value— Assets	[1]	621	2,128
Other Current Liabilities
Derivative [Line Items]
Fair Value— (Liabilities)		(1,047)	(1,830)
Other Current Liabilities | Designated as Hedging Instrument
Derivative [Line Items]
Fair Value— (Liabilities)		(1,047)	(1,830)
Other Current Liabilities | Designated as Hedging Instrument | Foreign currency contracts
Derivative [Line Items]
Fair Value— (Liabilities)	[1]	$ (1,047)	$ (1,830)

[1] Assets are included in prepaid expenses and other and liabilities are included in other accrued expenses on the accompanying consolidated balance sheets.