Guarantees (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2021	Apr. 30, 2020	Jul. 31, 2020
Guarantor Obligations
Royalty income	$ 765.0	$ 629.7	$ 2,080.8	$ 1,964.4
Advanced Filtration Systems, Inc.
Guarantor Obligations
Outstanding debt (the Company guarantees half)	34.2		34.2		$ 40.0
Contingent liability for standby letters of credit	7.7		7.7		7.5
Amounts drawn for letters of credit	0.0		0.0		$ 0.0
Investment earnings	0.8	0.8	1.4	1.2
Advanced Filtration Systems, Inc. | Royalty
Guarantor Obligations
Royalty income	$ 1.8	$ 1.6	$ 5.0	$ 5.2