Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value Measured on Recurring Basis $ in Thousands	Jan. 31, 2018 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivatives assets	$ 3,873
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivatives assets	3,873
Interest Rate Swap
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivatives assets	3,873
Interest Rate Swap | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivatives assets	$ 3,873