Derivative Financial Instruments - Summary of Combined Fair Value of Derivatives not Designated as Hedging Instruments included in Accompanying Condensed Consolidated Balance Sheet (Details) $ in Thousands	Jan. 31, 2018 USD ($)
Derivative Instruments – Interest Rate Swaps | Other Assets, Net | Not Designated As Hedging Instruments
Derivatives Fair Value [Line Items]
Fair value of derivatives	$ 3,873