Post Retirement Benefit Plans - Schedule of Other Comprehensive Income Included in Financial Statement (Detail) - USD ($) $ in Millions |
Oct. 31, 2016 |
Oct. 31, 2015 |
|---|---|---|
| Compensation and Retirement Disclosure [Abstract] | ||
| Unrecognized net actuarial gain | $ (2.2) | $ 1.6 |
| Unrecognized prior service credit | (4.3) | 5.8 |
| Accumulated other comprehensive income | $ (6.5) | $ 7.4 |