Post Retirement Benefit Plans - Schedule of Plan's Change in Benefit Obligation (Detail) - Other Postretirement Benefits Plan - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 13.6	$ 14.9
Interest cost	0.5	0.5	$ 0.7
Actuarial loss	(0.7)	(0.6)
Foreign currency effect	0.0	(0.1)
Benefits paid	(0.8)	(1.1)
Benefit obligation at end of year	$ 12.6	$ 13.6	$ 14.9