v3.7.0.1
Derivative Instruments - Gains (losses) Associated with Foreign Currency Forward Contracts (Detail) - USD ($)
$ in Thousands
3 Months Ended
Apr. 30, 2017
Apr. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative instruments, gain (loss) expected to be reclassified from accumulated OCI within the next 12 months $ 4,000  
Other expense, net    
Derivative Instruments, Gain (Loss) [Line Items]    
Foreign currency forward contracts not designated as hedges (6) $ (1,319)
Designated as Hedging Instrument | Revenues    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (losses) reclassified from OCI into income (effective portion) 234 110
Designated as Hedging Instrument | Other expense, net    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (losses) recognized in income (amount excluded from effectiveness testing and ineffective portion) 623 151
Designated as Hedging Instrument | Net change in market value of effective foreign currency forward exchange contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (losses) recognized in OCI (effective portion) $ (975) $ (10,954)