Derivative Instruments - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	$ 45,430,000	$ 51,623,000
Derivative foreign currency exchange contracts settlement date	2 months
Cash flow hedges [Member] | Interest rate contracts [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	$ 3,992,000	$ 0