v3.26.1
Note 3 - Segment Information - Segment Information (Details) - USD ($)
 3 Months Ended 9 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Sep. 30, 2025
Revenue $ 17,105,393 $ 17,264,615 $ 92,822,870 $ 81,016,198  
Operations and maintenance 5,122,000 4,587,672 15,963,447 14,599,534  
Taxes other than income taxes 833,127 750,067 2,529,755 2,287,068  
Depreciation and amortization 3,071,105 2,909,344 9,213,315 8,609,472  
Operating income (loss) 1,172,269 1,196,560 19,006,556 18,924,523  
Equity in earnings 764,178 772,082 2,495,239 2,427,470  
Interest expense 1,551,750 1,512,754 4,808,738 4,922,959  
Income before income taxes 713,663 699,888 18,219,433 17,610,003  
Assets 339,659,131   339,659,131   $ 329,839,566
Gross additions to utility property     16,074,186   20,730,140
Gross investment in affiliates     1,015,960 50,894 76,385
Gas Utility [Member]          
Revenue 17,082,066 17,239,550 92,750,085 80,938,690  
Cost of gas - utility 6,902,067 7,816,181 46,095,234 36,581,043  
Operating Segments [Member]          
Revenue 17,082,066 17,239,550 92,750,085 80,938,690  
Operations and maintenance 5,122,000 4,587,672 15,963,447 14,599,534  
Taxes other than income taxes 833,127 750,067 2,529,755 2,287,068  
Income before income taxes 695,161 679,614 18,161,211 17,547,053  
Assets 324,604,631   324,604,631   313,250,313
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]          
Revenue 23,327 25,065 72,785 77,508  
Operating income (loss) 4,825 4,791 14,563 14,558  
Income before income taxes 18,502 20,274 58,222 62,950  
Assets 15,054,500   15,054,500   16,589,253
Gas Utility [Member]          
Revenue 17,082,066 17,239,550 92,750,085 80,938,690  
Depreciation and amortization 3,071,105 2,909,344 9,213,315 8,609,472  
Operating income (loss) 1,177,694 1,219,977 19,039,786 18,978,672  
Equity in earnings 0 0 0 0  
Interest expense 927,062 822,022 2,959,096 2,796,978  
Income before income taxes 561,001 640,938 17,538,625 17,360,579  
Assets 301,324,252   301,324,252   291,571,159
Gross additions to utility property     16,074,186   20,730,140
Gross investment in affiliates     0   0
Gas Utility [Member] | Gas Utility [Member]          
Cost of gas - utility 6,902,067 7,816,181 46,095,234 36,581,043  
Gas Utility [Member] | Operating Segments [Member]          
Revenue 17,082,066 17,239,550 92,750,085 80,938,690  
Operations and maintenance 5,098,310 4,544,554 15,873,629 14,484,248  
Taxes other than income taxes 832,890 749,494 2,528,121 2,285,255  
Income before income taxes 561,001 640,938 17,538,625 17,360,579  
Assets 301,324,252   301,324,252   291,571,159
Gas Utility [Member] | Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]          
Revenue 0 0 0 0  
Operating income (loss) 0 0 0 0  
Income before income taxes 0 0 0 0  
Assets 0   0   0
Investment in Affiliates [Member]          
Revenue 0 0 0 0  
Depreciation and amortization 0 0 0 0  
Operating income (loss) (23,927) (43,691) (91,452) (117,099)  
Equity in earnings 764,178 772,082 2,495,239 2,427,470  
Interest expense 624,688 690,732 1,849,642 2,125,981  
Income before income taxes 134,160 38,676 622,586 186,474  
Assets 23,280,379   23,280,379   21,679,154
Gross additions to utility property     0   0
Gross investment in affiliates     1,015,960   76,385
Investment in Affiliates [Member] | Gas Utility [Member]          
Cost of gas - utility 0 0 0 0  
Investment in Affiliates [Member] | Operating Segments [Member]          
Revenue 0 0 0 0  
Operations and maintenance 23,690 43,118 89,818 115,286  
Taxes other than income taxes 237 573 1,634 1,813  
Income before income taxes 134,160 38,676 622,586 186,474  
Assets 23,280,379   23,280,379   21,679,154
Investment in Affiliates [Member] | Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]          
Revenue 0 0 0 0  
Operating income (loss) 0 0 0 0  
Income before income taxes 0 $ 0 0 $ 0  
Assets $ 0   $ 0   $ 0