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	Jul. 31, 2016	Oct. 31, 2015
Senior Notes due 2017
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair value	$ 307.2	$ 314.8
Senior Notes due 2019
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair value	282.5	280.6
Senior Notes due 2021
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair value	$ 266.9	$ 258.7