Post Retirement Benefit Plans - Fair Value Measurements for Pension Assets (Detail) - USD ($) $ in Millions	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets in the Fair Value Hierarchy	$ 297.6	$ 254.3
Investments Measured at Net Asset Value	271.0	372.0
Investments at Fair Value	568.6	626.3	$ 624.7
Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	126.0	163.2
Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	171.6	91.1
Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	0.0
Mutual funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	202.8	149.8
Mutual funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	76.7	104.9
Mutual funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	126.1	44.9
Mutual funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	0.0
Common stock
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	40.0	39.7
Common stock | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	40.0	39.7
Common stock | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	0.0
Common stock | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	0.0
Cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	9.3	18.6
Cash | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	9.3	18.6
Cash | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	0.0
Cash | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	0.0
Corporate bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	23.1	29.7
Corporate bonds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	0.0
Corporate bonds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	23.1	29.7
Corporate bonds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	0.0
Government bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	18.5	16.5
Government bonds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	0.0
Government bonds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	18.5	16.5
Government bonds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0	$ 0.0
Other assets
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	3.9
Other assets | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	0.0
Other assets | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	3.9
Other assets | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Investments at Fair Value	$ 0.0