Restructuring Charges - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016	Oct. 31, 2016
Restructuring and Related Costs [Line Items]
Restructuring charges	$ 3.9	$ 10.2	$ 8.7	$ 17.9
Amounts Remaining to be Incurred	19.9		19.9		$ 16.1
Employee Separation Costs
Restructuring and Related Costs [Line Items]
Restructuring charges	2.9		6.8
Other Costs
Restructuring and Related Costs [Line Items]
Restructuring charges	$ 1.0		$ 1.9