Restructuring Charges - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Oct. 31, 2017
Restructuring and Related Costs [Line Items]
Restructuring charges	$ 4.1	$ (0.3)
Amounts Remaining to be Incurred	16.1		$ 14.9
Employee Separation Costs
Restructuring and Related Costs [Line Items]
Restructuring charges	2.8
Other Costs
Restructuring and Related Costs [Line Items]
Restructuring charges	$ 1.3