Note 3 - Segment Information - Segment Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Sep. 30, 2025
Revenue	$ 30,260,468	$ 27,289,486
Operations and maintenance	5,222,481	4,688,671
Taxes other than income taxes	830,058	722,376
Depreciation and amortization	3,071,105	2,843,360
Operating income (loss)	6,550,337	7,328,021
Equity in earnings	827,070	854,213
Interest expense	1,671,150	1,779,930
Income before income taxes	6,211,246	6,875,640
Assets	341,043,733		$ 329,839,566
Gross additions to utility property	5,643,552	5,748,177	20,730,140
Gross investment in affiliates	542,893	17,738	76,385
Gas Utility [Member]
Revenue	30,235,141	27,263,204
Cost of gas - utility	14,581,615	11,702,709
Operating Segments [Member]
Revenue	30,235,141	27,263,204
Operations and maintenance	5,222,481	4,688,671
Taxes other than income taxes	830,058	722,376
Income before income taxes	6,190,791	6,853,707
Assets	328,126,571		313,250,313
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenue	25,327	26,282
Operating income (loss)	4,872	4,349
Income before income taxes	20,455	21,933
Assets	12,917,162		16,589,253
Gas Utility [Member]
Revenue	30,235,141	27,263,204
Depreciation and amortization	3,071,105	2,843,360
Operating income (loss)	6,569,357	7,341,276
Equity in earnings	0	0
Interest expense	1,044,907	1,032,409
Income before income taxes	6,010,484	6,781,658
Assets	305,806,756		291,571,159
Gross additions to utility property	5,643,552		20,730,140
Gross investment in affiliates	0		0
Gas Utility [Member] \| Gas Utility [Member]
Cost of gas - utility	14,581,615	11,702,709
Gas Utility [Member] \| Operating Segments [Member]
Revenue	30,235,141	27,263,204
Operations and maintenance	5,183,624	4,653,956
Taxes other than income taxes	829,440	721,903
Income before income taxes	6,010,484	6,781,658
Assets	305,806,756		291,571,159
Gas Utility [Member] \| Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenue	0	0
Operating income (loss)	0	0
Income before income taxes	0	0
Assets	0		0
Investment in Affiliates [Member]
Revenue	0	0
Depreciation and amortization	0	0
Operating income (loss)	(39,475)	(35,188)
Equity in earnings	827,070	854,213
Interest expense	626,243	747,521
Income before income taxes	180,307	72,049
Assets	22,319,815		21,679,154
Gross additions to utility property	0		0
Gross investment in affiliates	542,893		76,385
Investment in Affiliates [Member] \| Gas Utility [Member]
Cost of gas - utility	0	0
Investment in Affiliates [Member] \| Operating Segments [Member]
Revenue	0	0
Operations and maintenance	38,857	34,715
Taxes other than income taxes	618	473
Income before income taxes	180,307	72,049
Assets	22,319,815		21,679,154
Investment in Affiliates [Member] \| Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenue	0	0
Operating income (loss)	0	0
Income before income taxes	0	$ 0
Assets	$ 0		$ 0

RGC RESOURCES INC 10-Q