Foreign Exchange Hedging Facility - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2014
Dec. 31, 2013
Dec. 09, 2011
Derivative Instruments, Gain (Loss) [Line Items]        
Obligations under restricted cash   $ 0 $ 0  
Foreign Exchange Forward [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Obligations under restricted cash       1,000,000
Loss on hedging transactions $ 48,000      
Termination date of facility 2013-02