Derivative Financial Instruments Designated as Cash Flow Hedges (Details) - USD ($)	3 Months Ended		12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Oct. 31, 2017	Oct. 31, 2013
Senior Notes 2027 [Member]
Derivative Cash Flow Hedge [Line Items]
Notional value of derivative liability entered into in conjunction with the issuance of the Senior Notes			$ 125,000,000
Amount hedged by the treasury lock entered into in conjunction with the issuance of the Senior Notes			125,000,000
Prinicipal amount of debt issued			$ 300,000,000
Interest rate on unsecured senior note debt			3.50%
Gain (loss) expected to be reclassified as interest expense on derivative financial instruments designated as cash flow hedges, over the next twelve months	$ (68,000)
Unamortized gain (loss) on interest rate lock	(600,000)
Loss reclassified to interest expense on derivative financial instruments designated as cash flow hedges	17,000
Loss on hedge from treasury lock entered into in conjunction with the issuance of the Senior Notes			$ 700,000
Income tax benefit on losess from treasury lock entered into in conjunction with the issuance of the Senior Notes			$ 300,000
Senior Notes 2023 [Member]
Derivative Cash Flow Hedge [Line Items]
Interest rate on unsecured senior note debt				3.625%
Gain reclassified to interest expense on derivative financial instruments designated as cash flow hedges	50,000	$ 50,000
Gain (loss) expected to be reclassified as interest expense on derivative financial instruments designated as cash flow hedges, over the next twelve months	200,000
Unamortized gain (loss) on interest rate lock	$ 1,100,000