Financial Instruments And Fair Value Measurements - Estimated Fair Values for the Company's Senior Notes and Assets Held by Special Purpose Entities (Detail) - Estimate of Fair Value Measurement - USD ($) $ in Millions	Oct. 31, 2018	Oct. 31, 2017
Estimated Fair Value Of Financial Instruments [Line Items]
Assets held by special purpose entities estimated fair value	$ 51.6	$ 52.5
Senior Notes due 2019
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair value of debt instruments	257.4	272.0
Senior Notes due 2021
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair value of debt instruments	$ 263.4	$ 281.0