Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jan. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Tax charge for re-measurement of net deferred tax asset	$ 1.4
Tax charge on repatriated earnings of non-U.S. subsidiaries	108.3
Noncurrent portion of repatriated earnings of non-U.S. subsidiaries	99.4
Unrecognized tax benefits	19.8
Accrued interest and penalties on unrecognized tax benefits	2.6
Unrecognized tax benefits that could potentially expire	$ 2.4
Forecast
U.S. federal statutory tax rate		21.00%	26.90%