Note 2 - Revenue - Disaggregation of Revenue (Details) - USD ($)	3 Months Ended	9 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Total contracts with customers	$ 13,552,645	$ 13,418,853	$ 67,729,290	$ 82,101,702
Alternative revenue programs	905,557	241,392	3,807,640	2,870,535
Operating revenues	14,458,202	13,660,245	71,536,930	84,972,237
Oil and Gas [Member] \| Residential [Member]
Total contracts with customers	7,333,332	7,405,959	40,001,039	48,148,235
Oil and Gas [Member] \| Commercial [Member]
Total contracts with customers	4,706,086	4,459,667	22,946,163	28,502,754
Oil and Gas [Member] \| Transportation and Interruptible [Member]
Total contracts with customers	1,317,890	1,354,678	4,047,151	4,508,997
Product and Service, Other [Member]
Total contracts with customers	195,337	198,549	734,937	941,716
Gas Utility [Member]
Total contracts with customers	13,525,822	13,390,464	67,647,924	82,015,065
Alternative revenue programs	905,557	241,392	3,807,640	2,870,535
Operating revenues	14,431,379	13,631,856	71,455,564	84,885,600
Gas Utility [Member] \| Oil and Gas [Member] \| Residential [Member]
Total contracts with customers	7,333,332	7,405,959	40,001,039	48,148,235
Gas Utility [Member] \| Oil and Gas [Member] \| Commercial [Member]
Total contracts with customers	4,706,086	4,459,667	22,946,163	28,502,754
Gas Utility [Member] \| Oil and Gas [Member] \| Transportation and Interruptible [Member]
Total contracts with customers	1,317,890	1,354,678	4,047,151	4,508,997
Gas Utility [Member] \| Product and Service, Other [Member]
Total contracts with customers	168,514	170,160	653,571	855,079
Non-utility [Member]
Total contracts with customers	26,823	28,389	81,366	86,637
Alternative revenue programs	0	0	0	0
Operating revenues	26,823	28,389	81,366	86,637
Non-utility [Member] \| Oil and Gas [Member] \| Residential [Member]
Total contracts with customers	0	0	0	0
Non-utility [Member] \| Oil and Gas [Member] \| Commercial [Member]
Total contracts with customers	0	0	0	0
Non-utility [Member] \| Oil and Gas [Member] \| Transportation and Interruptible [Member]
Total contracts with customers	0	0	0	0
Non-utility [Member] \| Product and Service, Other [Member]
Total contracts with customers	$ 26,823	$ 28,389	$ 81,366	$ 86,637