Note 3 - Revenue - Disaggregation of Revenue (Details) - USD ($)	3 Months Ended	6 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Total contracts with customers	$ 29,112,484	$ 28,046,986	$ 51,279,035	$ 46,701,595
Alternative Revenue Programs	417,199	206,676	1,513,728	1,069,084
Operating revenues	29,529,683	28,253,662	52,792,763	47,770,679
Oil and Gas [Member] \| Residential [Member]
Total contracts with customers	18,104,512	17,402,552	31,317,001	28,648,746
Oil and Gas [Member] \| Commercial [Member]
Total contracts with customers	9,487,312	9,264,611	16,873,030	15,254,631
Oil and Gas [Member] \| Industrial and Transportation [Member]
Total contracts with customers	1,352,161	1,252,343	2,665,252	2,476,144
Product and Service, Other [Member]
Total contracts with customers	168,499	127,480	423,752	322,074
Gas Utility [Member]
Total contracts with customers	29,082,020	28,014,598	51,217,146	46,635,690
Alternative Revenue Programs	417,199	206,676	1,513,728	1,069,084
Operating revenues	29,499,219	28,221,274	52,730,874	47,704,774
Gas Utility [Member] \| Oil and Gas [Member] \| Residential [Member]
Total contracts with customers	18,104,512	17,402,552	31,317,001	28,648,746
Gas Utility [Member] \| Oil and Gas [Member] \| Commercial [Member]
Total contracts with customers	9,487,312	9,264,611	16,873,030	15,254,631
Gas Utility [Member] \| Oil and Gas [Member] \| Industrial and Transportation [Member]
Total contracts with customers	1,352,161	1,252,343	2,665,252	2,476,144
Gas Utility [Member] \| Product and Service, Other [Member]
Total contracts with customers	138,035	95,092	361,863	256,169
Non-utility [Member]
Total contracts with customers	30,464	32,388	61,889	65,905
Alternative Revenue Programs	0	0	0	0
Operating revenues	30,464	32,388	61,889	65,905
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] \| Industrial and Transportation [Member]
Total contracts with customers	0	0	0	0
Non-utility [Member] \| Product and Service, Other [Member]
Total contracts with customers	$ 30,464	$ 32,388	$ 61,889	$ 65,905