Post Retirement Benefit Plans - Components of Net Periodic Cost for Postretirement Benefits (Detail) - Other Postretirement Benefit Plans, Defined Benefit - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.0	$ 0.0
Interest cost	0.1	0.1
Amortization of prior service cost and net actuarial gain	(0.3)	(0.4)
Net periodic costs (benefits) for pension and postretirement benefits	$ (0.2)	$ (0.3)