Guarantees (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Apr. 30, 2025	Apr. 30, 2024	Apr. 30, 2025	Apr. 30, 2024	Jul. 31, 2024
Advanced Filtration Systems, Inc.
Guarantor Obligations
Investment earnings	$ 3,900,000	$ 4,300,000	$ 10,200,000	$ 8,500,000
Revolving credit facility
Guarantor Obligations
Available credit facilities	63,000,000		63,000,000
Multi-Currency Revolving Credit Facility
Guarantor Obligations
Available credit facilities	17,000,000		17,000,000
Advanced Filtration Systems, Inc.
Guarantor Obligations
AFSI outstanding debt	$ 45,500,000		$ 45,500,000		$ 51,000,000.0