Note 11 - Supplemental Financial Data - Oil and Gas Producing Activities (Unaudited): Summary of Changes Present Value of Estimated Future Net Revenue (Details) - USD ($)	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Details
Present value of estimated future net revenue, beginning of year	$ 72,000	$ 66,000
Oil and Gas, Standardized Measure, Discounted Future Net Cash Flow, Sale and Transfer of Oil and Gas Produced	(16,000)	(20,000)
Oil and Gas, Standardized Measure, Discounted Future Net Cash Flow, Sale and Transfer Prices and Production Cost, Increase (Decrease)	(8,900)	0
Revisions of quantity estimates	24,000	29,000
Accretion Expense	8,000	7,000
Oil and Gas, Standardized Measure, Discounted Future Net Cash Flow, Other	(8,100)	(10,000)
Oil and Gas, Standardized Measure, Discounted Future Net Cash Flow, Future Net Cash Flow, after Discount	$ 71,000	$ 72,000