Post Retirement Benefit Plans - Schedule of Plan's Change in Benefit Obligation (Details) - Other Postretirement Benefits Plan - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 10.7	$ 12.6
Interest cost	0.5	0.5	$ 0.5
Actuarial loss (gain)	0.5	(1.4)
Benefits paid	(1.0)	(1.0)
Acquisition	1.5	0.0
Benefit obligation at end of year	$ 12.2	$ 10.7	$ 12.6