Credit Arrangements (Narrative) (Details) - USD ($)	12 Months Ended
	Aug. 31, 2024	Aug. 31, 2023
Debt Instrument [Line Items]
Long-term Debt	$ 115,492,000	$ 115,710,000
Elecsys Series 2006A Bonds [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 492,000	710,000
Maturity date	Sep. 01, 2026
Variable interest rate	0.45%
Effective interest rate	2.06%
Interest rate adjustment period	5 years
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date	Aug. 26, 2026
Unsecured revolving line of credit, amount outstanding	$ 0	0
Line of Credit Facility, Remaining Borrowing Capacity	50,000,000
Line of credit facility, additional borrowing capacity	$ 50,000,000
Variable interest rate	6.67%
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	us-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Annual commitment fee	0.125%
Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Variable interest rate	100.00%
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	us-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Annual commitment fee	0.125%
Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Unsecured revolving line of credit, maximum borrowing capacity outstanding	$ 50,000,000
Variable interest rate	210.00%
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	us-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Annual commitment fee	0.20%
Unsecured Senior Notes, Series A [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 115,000,000	$ 115,000,000
Face amount	$ 115,000,000
Maturity date	Feb. 19, 2030
Interest rate	3.82%