Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Guarantees (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
Guarantees (Narrative) (Details) - USD ($)	Jan. 31, 2023	Jan. 31, 2022	Jan. 31, 2023	Jan. 31, 2022	Jul. 31, 2022
Guarantor Obligations
Investment earnings	$ 500,000	$ 2,000,000	$ 1,800,000	$ 3,200,000
Unsecured 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	$ 64,800,000		$ 64,800,000		$ 68,800,000