Income Taxes (NOL and Tax Credit Valuation Allowances) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2022	Jul. 31, 2021	Jul. 31, 2020
Valuation Allowance, Deferred Tax Asset
Balance as of beginning of year	$ (4.6)	$ (8.1)	$ (4.4)
Additions charged to costs and expenses	(0.9)	(0.8)	(3.7)
Deductions from reserves	2.1	4.3	0.0
Balance as of end of year	$ (3.4)	$ (4.6)	$ (8.1)