Derivative Instruments - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2013 EUR (€)	Dec. 31, 2012 USD ($)	Dec. 31, 2012 EUR (€)	Sep. 30, 2013 Prepaid Expenses and Other Current Assets USD ($)	Dec. 31, 2012 Prepaid Expenses and Other Current Assets USD ($)	Sep. 30, 2013 Other Long Lived Assets USD ($)	Dec. 31, 2012 Other Long Lived Assets USD ($)
Derivatives Fair Value [Line Items]
Foreign currency forward contracts, notional amount	$ 12,900,000		$ 12,900,000		€ 9,500,000	$ 22,200,000	€ 16,800,000
Derivative assets								239,000	30,000	27,000	21,000
Foreign currency forward contracts unrealized gain (loss)	450,000	243,000	97,000	(450,000)
Foreign currency forward contracts realized gain (loss)	$ 45,000	$ 0	$ 118,000	$ 0