Derivative Instruments and Hedging Activities - Effect of Derivative Instruments on Consolidated Statements of Operations and Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain / (Loss) recognized in OCI on Derivatives	$ (51)	$ 20	$ (16)	$ (75)
Currency Forward Contracts [Member] | Cash Flow Hedging Relationships [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain / (Loss) recognized in OCI on Derivatives	(51)	20	(16)	(75)
Currency Forward Contracts [Member] | Cash Flow Hedging Relationships [Member] | SG&A Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain / (Loss) reclassified from Accumulated OCI to Income (Expense)	29	(16)	33	(12)
Currency Forward Contracts [Member] | Cash Flow Hedging Relationships [Member] | Other Income/(Expense) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain / (Loss) recognized in Income (Expense) on Derivatives	$ (1)	$ (40)	$ 67	$ 1