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Fair value of financial instruments
3 Months Ended
Apr. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Fair Value Disclosures [Text Block]
Fair Value

The carrying values of cash and cash equivalents, accounts receivable and accounts payable are reasonable estimates of their fair value due to their short-term nature. The carrying amount of the Company's short-term debt, revolving line of credit and long-term debt approximate fair value, because the majority of the amounts outstanding accrue interest at variable market rates.