Note 2 - Revenue - Disaggregation of Revenue (Details) - USD ($)	3 Months Ended	6 Months Ended
Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Total contracts with customers	$ 36,458,285	$ 30,818,621	$ 63,302,960	$ 54,176,645
Alternative revenue programs	3,812	1,840,755	448,623	2,902,083
Revenue	36,462,097	32,659,376	63,751,583	57,078,728
Oil and Gas [Member] \| Residential [Member]
Total contracts with customers	22,591,822	18,843,065	38,413,706	32,667,707
Oil and Gas [Member] \| Commercial [Member]
Total contracts with customers	12,210,961	10,398,801	21,455,956	18,240,077
Oil and Gas [Member] \| Transportation and Interruptible [Member]
Total contracts with customers	1,476,042	1,358,991	2,981,745	2,729,261
Product and Service, Other [Member]
Total contracts with customers	179,460	217,764	451,553	539,600
Gas Utility [Member]
Total contracts with customers	36,432,124	30,791,576	63,250,517	54,122,102
Alternative revenue programs	3,812	1,840,755	448,623	2,902,083
Revenue	36,435,936	32,632,331	63,699,140	57,024,185
Gas Utility [Member] \| Oil and Gas [Member] \| Residential [Member]
Total contracts with customers	22,591,822	18,843,065	38,413,706	32,667,707
Gas Utility [Member] \| Oil and Gas [Member] \| Commercial [Member]
Total contracts with customers	12,210,961	10,398,801	21,455,956	18,240,077
Gas Utility [Member] \| Oil and Gas [Member] \| Transportation and Interruptible [Member]
Total contracts with customers	1,476,042	1,358,991	2,981,745	2,729,261
Gas Utility [Member] \| Product and Service, Other [Member]
Total contracts with customers	153,299	190,719	399,110	485,057
Non-utility [Member]
Total contracts with customers	26,161	27,045	52,443	54,543
Alternative revenue programs	0	0	0	0
Revenue	26,161	27,045	52,443	54,543
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	$ 26,161	$ 27,045	$ 52,443	$ 54,543