Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended	12 Months Ended
	Apr. 30, 2018	Jan. 31, 2018	Apr. 30, 2018	Jul. 31, 2019	Jul. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Tax charge (benefit) for re-measurement of net deferred tax asset	$ 4.2	$ 1.4
Tax benefits from remeasurement of deferred tax assets	4.9
Tax charge on repatriated earnings of non-U.S. subsidiaries	4.6	$ 108.3	$ 112.9
Noncurrent portion of repatriated earnings of non-U.S. subsidiaries	103.5		103.5
Unrecognized tax benefits	19.7		19.7
Accrued interest and penalties on unrecognized tax benefits	2.8		2.8
Unrecognized tax benefits that could potentially expire	2.4		$ 2.4
Forecast
Defined Benefit Plan Disclosure [Line Items]
U.S. federal statutory tax rate				21.00%	26.90%
Pension Plan | United States
Defined Benefit Plan Disclosure [Line Items]
Employer discretionary contribution	$ 35.0