Derivative Instruments and Hedging Activities - Gain or Loss Recognized on Foreign Currency Forward Contracts (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Gain or loss recognized on foreign currency forward contracts			$ (348,000)	$ 142,000
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contracts [Member] | Other gain (loss), net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or loss recognized on foreign currency forward contracts	$ (21,000)	$ 312,000	$ (348,000)	$ 142,000