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Derivative Financial Instruments - Additional Information (Details)
12 Months Ended
Jan. 31, 2019
USD ($)
Jan. 31, 2018
USD ($)
Jan. 31, 2017
USD ($)
Jan. 31, 2019
EUR (€)
Jan. 31, 2019
GBP (£)
Jan. 31, 2019
CHF (SFr)
Derivatives Fair Value [Line Items]            
Maximum length of time hedged in cash flow hedge 12 months          
Amounts reclassified from accumulated other comprehensive income (loss) $ 360 $ (926) $ 371      
Net Unrealized Income (Loss) On Hedging Contracts            
Derivatives Fair Value [Line Items]            
Amounts reclassified from accumulated other comprehensive income (loss) 400,000 (900,000)        
Accumulated other comprehensive income, tax expense (benefit) $ 100,000 $ (200,000)        
Foreign Exchange Forward            
Derivatives Fair Value [Line Items]            
Net forward contracts hedging portfolio       € 8,300,000 £ 400,000 SFr 33,000,000
Maximum            
Derivatives Fair Value [Line Items]            
Expiry dates ranging Jul. 10, 2019