Post Retirement Benefit Plans - Components of Net Periodic Pension Cost (Detail) - Pension Plans, Defined Benefit - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3.3	$ 3.1
Interest cost	4.6	5.6
Expected return on plan assets	(7.1)	(8.3)
Amortization of prior service cost and net actuarial loss	2.8	2.9
Net periodic costs (benefits) for pension and postretirement benefits	$ 3.6	$ 3.3