Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Operating revenues	$ 145,713	$ 147,998	$ 337,049	$ 365,251
Equity in earnings of investment			5,526	5,240
Net Income (Loss)	23,794	28,681	57,608	59,759
Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	120,383	121,492	236,508	238,736
Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	25,116	26,291	100,285	126,253
Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	214	215	256	262
Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	145,713	147,998	337,049	365,251
Equity in earnings of investment	2,780	2,629	5,526	5,240
Net Income (Loss)	23,794	28,681	57,608	59,759
Operating Segments [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	120,328	121,685	236,399	238,877
Equity in earnings of investment	0	0	0	0
Net Income (Loss)	15,661	21,556	31,424	34,870
Operating Segments [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	27,288	29,061	107,668	135,684
Equity in earnings of investment	0	0	0	0
Net Income (Loss)	50	581	10,664	11,340
Operating Segments [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	11,160	10,410	22,029	21,007
Equity in earnings of investment	0	0	0	0
Net Income (Loss)	6,043	5,470	11,866	11,040
Operating Segments [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Equity in earnings of investment	2,780	2,629	5,526	5,240
Net Income (Loss)	2,022	1,914	4,018	3,813
Operating Segments [Member] | All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Equity in earnings of investment	0	0	0	0
Net Income (Loss)	18	(840)	(364)	(1,304)
Consolidation Elimination Entries [Member]
Segment Reporting Information [Line Items]
Operating revenues	(13,063)	(13,158)	(29,047)	(30,317)
Equity in earnings of investment	0	0	0	0
Net Income (Loss)	0	0	0	0
Consolidation Elimination Entries [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	(55)	193	(109)	141
Consolidation Elimination Entries [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	2,172	2,770	7,383	9,431
Consolidation Elimination Entries [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	10,946	10,195	21,773	20,745
Consolidation Elimination Entries [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Consolidation Elimination Entries [Member] | All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
MGE [Member]
Segment Reporting Information [Line Items]
Operating revenues	145,713	147,998	337,049	365,251
Net Income (Loss)	15,988	22,232	42,591	46,355
MGE [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	120,383	121,492	236,508	238,736
MGE [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	25,116	26,291	100,285	126,253
MGE [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	214	215	256	262
MGE [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	145,713	147,998	337,049	365,251
Net Income (Loss)	15,988	22,232	42,591	46,355
MGE [Member] | Operating Segments [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	120,328	121,685	236,399	238,877
Net Income (Loss)	15,661	21,556	31,424	34,870
MGE [Member] | Operating Segments [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	27,288	29,061	107,668	135,684
Net Income (Loss)	50	581	10,664	11,340
MGE [Member] | Operating Segments [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	11,160	10,410	22,029	21,007
Net Income (Loss)	6,043	5,470	11,866	11,040
MGE [Member] | Consolidation Elimination Entries [Member]
Segment Reporting Information [Line Items]
Operating revenues	(13,063)	(13,158)	(29,047)	(30,317)
Net Income (Loss)	(5,766)	(5,375)	(11,363)	(10,895)
MGE [Member] | Consolidation Elimination Entries [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	(55)	193	(109)	141
MGE [Member] | Consolidation Elimination Entries [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	2,172	2,770	7,383	9,431
MGE [Member] | Consolidation Elimination Entries [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	$ 10,946	$ 10,195	$ 21,773	$ 20,745