Financial Instruments And Fair Value Measurements - Estimated Fair Values for the Company's Senior Notes and Assets Held by Special Purpose Entities (Detail) - USD ($) $ in Millions	Oct. 31, 2017	Oct. 31, 2016
Estimated Fair Value Of Financial Instruments [Line Items]
Assets held by special purpose entities estimated fair value	$ 50.9	$ 50.9
Estimate of Fair Value Measurement
Estimated Fair Value Of Financial Instruments [Line Items]
Assets held by special purpose entities estimated fair value	52.5	54.3
Senior Notes due 2017 | Estimate of Fair Value Measurement
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair value of debt instruments	0.0	302.4
Senior Notes due 2019 | Estimate of Fair Value Measurement
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair value of debt instruments	272.0	280.1
Senior Notes due 2021 | Estimate of Fair Value Measurement
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair value of debt instruments	$ 281.0	$ 264.9