Restructuring and Related Costs - Restructuring and Related Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Restructuring Reserve [Roll Forward]
Balance, beginning of period			$ 8.4
Costs recognized	$ 2.9	$ 5.2	22.5	$ 16.0
Payments			(21.0)
Non-cash charges			(1.1)
Balance, end of period	8.8		8.8
Employee Severance
Restructuring Reserve [Roll Forward]
Balance, beginning of period			2.7
Costs recognized			10.8
Payments			(8.9)
Non-cash charges			0.0
Balance, end of period	4.6		4.6
Lease Exit
Restructuring Reserve [Roll Forward]
Balance, beginning of period			2.8
Costs recognized			2.5
Payments			(1.2)
Non-cash charges			(1.1)
Balance, end of period	3.1		3.1
Other Project Fees
Restructuring Reserve [Roll Forward]
Balance, beginning of period			0.4
Costs recognized			5.1
Payments			(4.4)
Non-cash charges			0.0
Balance, end of period	1.1		1.1
External Support Fees
Restructuring Reserve [Roll Forward]
Balance, beginning of period			2.5
Costs recognized			4.0
Payments			(6.5)
Non-cash charges			0.0
Balance, end of period	$ 0.0		$ 0.0