Restructuring and Related Costs - Restructuring and Related Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Restructuring Reserve [Roll Forward]
Balance, beginning of period			$ 8.6
Costs recognized	$ 2.7	$ 5.3	6.5	$ 19.6
Payments			(6.8)
Balance, end of period	8.3		8.3
Employee severance
Restructuring Reserve [Roll Forward]
Balance, beginning of period			3.8
Costs recognized			3.1
Payments			(3.2)
Balance, end of period	3.7		3.7
Lease exit costs and asset impairment
Restructuring Reserve [Roll Forward]
Balance, beginning of period			3.1
Costs recognized			0.7
Payments			(0.6)
Balance, end of period	3.2		3.2
Other project fees
Restructuring Reserve [Roll Forward]
Balance, beginning of period			1.8
Costs recognized			2.7
Payments			(3.1)
Balance, end of period	$ 1.5		$ 1.5