Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019	Oct. 31, 2019
Income Tax Disclosure [Abstract]
Effective income tax rate	16.90%	5.40%	9.00%	0.90%
Unrecognized tax benefits	$ 56.8		$ 56.8		$ 49.7
Unrecognized tax benefits that could be settled during the next twelve months	$ 19.5		$ 19.5