Segment Information (Details)
$ in Thousands |
3 Months Ended |
6 Months Ended |
|
Jun. 30, 2026
USD ($)
|
Jun. 30, 2025
USD ($)
|
Jun. 30, 2026
USD ($)
Segment
|
Jun. 30, 2025
USD ($)
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
$ 161,195
|
$ 159,452
|
$ 403,898
|
$ 378,422
|
| Depreciation and amortization |
|
(28,939)
|
(28,354)
|
(57,028)
|
(56,032)
|
| Income tax (provision) benefit |
|
(4,279)
|
(2,975)
|
(10,135)
|
(9,271)
|
| Equity in earnings of investment |
|
|
|
7,336
|
6,241
|
| Net Income (Loss) |
|
33,353
|
26,498
|
81,834
|
68,090
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
$ 210,906
|
111,753
|
| Number of Reportable Segments | Segment |
|
|
|
4
|
|
| Electric [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
131,380
|
129,313
|
$ 262,760
|
254,767
|
| Gas [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
29,601
|
29,925
|
140,864
|
123,406
|
| Non Regulated Energy [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
214
|
214
|
274
|
249
|
| Transmission Investment [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
0
|
0
|
0
|
0
|
| All Others [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
0
|
0
|
0
|
0
|
| Operating Segments [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
161,195
|
159,452
|
403,898
|
378,422
|
| Fuel and purchased power |
|
(18,720)
|
(21,854)
|
(41,496)
|
(43,801)
|
| Purchased gas costs |
|
(9,285)
|
(11,313)
|
(80,108)
|
(65,277)
|
| Depreciation and amortization |
|
(28,939)
|
(28,354)
|
(57,028)
|
(56,032)
|
| Interest expense |
|
(11,236)
|
(9,142)
|
(22,374)
|
(18,304)
|
| Other segment items |
[1] |
(59,178)
|
(62,376)
|
(118,259)
|
(123,888)
|
| Income tax (provision) benefit |
|
(4,279)
|
(2,975)
|
(10,135)
|
(9,271)
|
| Equity in earnings of investment |
|
3,795
|
3,060
|
7,336
|
6,241
|
| Net Income (Loss) |
|
33,353
|
26,498
|
81,834
|
68,090
|
| Operating Segments [Member] | Electric [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
131,370
|
129,285
|
262,742
|
254,691
|
| Fuel and purchased power |
|
(19,509)
|
(22,524)
|
(43,582)
|
(45,630)
|
| Purchased gas costs |
|
0
|
0
|
0
|
0
|
| Depreciation and amortization |
|
(21,959)
|
(22,094)
|
(43,213)
|
(43,629)
|
| Interest expense |
|
(8,168)
|
(6,485)
|
(16,247)
|
(12,978)
|
| Other segment items |
[1] |
(57,877)
|
(58,130)
|
(113,151)
|
(114,109)
|
| Income tax (provision) benefit |
|
(1,237)
|
(472)
|
1,744
|
1,430
|
| Equity in earnings of investment |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) |
|
22,620
|
19,580
|
48,293
|
39,775
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
174,157
|
83,034
|
| Operating Segments [Member] | Gas [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
31,796
|
32,483
|
152,073
|
132,436
|
| Fuel and purchased power |
|
0
|
0
|
0
|
0
|
| Purchased gas costs |
|
(10,702)
|
(13,211)
|
(89,256)
|
(72,501)
|
| Depreciation and amortization |
|
(4,999)
|
(4,347)
|
(9,864)
|
(8,579)
|
| Interest expense |
|
(2,250)
|
(1,768)
|
(4,473)
|
(3,531)
|
| Other segment items |
[1] |
(15,372)
|
(15,015)
|
(30,977)
|
(31,111)
|
| Income tax (provision) benefit |
|
599
|
561
|
(4,664)
|
(4,426)
|
| Equity in earnings of investment |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) |
|
(928)
|
(1,297)
|
12,839
|
12,288
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
28,308
|
22,975
|
| Operating Segments [Member] | Non Regulated Energy [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
11,790
|
11,335
|
23,268
|
22,474
|
| Fuel and purchased power |
|
0
|
0
|
0
|
0
|
| Purchased gas costs |
|
0
|
0
|
0
|
0
|
| Depreciation and amortization |
|
(1,981)
|
(1,913)
|
(3,951)
|
(3,824)
|
| Interest expense |
|
(818)
|
(889)
|
(1,654)
|
(1,795)
|
| Other segment items |
[1] |
(30)
|
(23)
|
(81)
|
(67)
|
| Income tax (provision) benefit |
|
(2,441)
|
(2,318)
|
(4,789)
|
(4,573)
|
| Equity in earnings of investment |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) |
|
6,520
|
6,192
|
12,793
|
12,215
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
8,441
|
5,744
|
| Operating Segments [Member] | Transmission Investment [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
0
|
0
|
0
|
0
|
| Fuel and purchased power |
|
0
|
0
|
0
|
0
|
| Purchased gas costs |
|
0
|
0
|
0
|
0
|
| Depreciation and amortization |
|
0
|
0
|
0
|
0
|
| Interest expense |
|
0
|
0
|
0
|
0
|
| Other segment items |
[1] |
0
|
0
|
0
|
0
|
| Income tax (provision) benefit |
|
(1,034)
|
(835)
|
(1,999)
|
(1,702)
|
| Equity in earnings of investment |
|
3,795
|
3,060
|
7,336
|
6,241
|
| Net Income (Loss) |
|
2,761
|
2,225
|
5,337
|
4,539
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
0
|
0
|
| Operating Segments [Member] | Total Reportable Segments |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
174,956
|
173,103
|
438,083
|
409,601
|
| Fuel and purchased power |
|
(19,509)
|
(22,524)
|
(43,582)
|
(45,630)
|
| Purchased gas costs |
|
(10,702)
|
(13,211)
|
(89,256)
|
(72,501)
|
| Depreciation and amortization |
|
(28,939)
|
(28,354)
|
(57,028)
|
(56,032)
|
| Interest expense |
|
(11,236)
|
(9,142)
|
(22,374)
|
(18,304)
|
| Other segment items |
[1] |
(73,279)
|
(73,168)
|
(144,209)
|
(145,287)
|
| Income tax (provision) benefit |
|
(4,113)
|
(3,064)
|
(9,708)
|
(9,271)
|
| Equity in earnings of investment |
|
3,795
|
3,060
|
7,336
|
6,241
|
| Net Income (Loss) |
|
30,973
|
26,700
|
79,262
|
68,817
|
| Operating Segments [Member] | All Others [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
0
|
0
|
0
|
0
|
| Fuel and purchased power |
|
0
|
0
|
0
|
0
|
| Purchased gas costs |
|
0
|
0
|
0
|
0
|
| Depreciation and amortization |
|
0
|
0
|
0
|
0
|
| Interest expense |
|
0
|
0
|
0
|
0
|
| Other segment items |
[1] |
2,546
|
(291)
|
2,999
|
(727)
|
| Income tax (provision) benefit |
|
(166)
|
89
|
(427)
|
0
|
| Equity in earnings of investment |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) |
|
2,380
|
(202)
|
2,572
|
(727)
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
0
|
0
|
| Consolidation Elimination Entries [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
(13,761)
|
(13,651)
|
(34,185)
|
(31,179)
|
| Fuel and purchased power |
|
789
|
670
|
2,086
|
1,829
|
| Purchased gas costs |
|
1,417
|
1,898
|
9,148
|
7,224
|
| Depreciation and amortization |
|
0
|
0
|
0
|
0
|
| Interest expense |
|
0
|
0
|
0
|
0
|
| Other segment items |
[1] |
11,555
|
11,083
|
22,951
|
22,126
|
| Income tax (provision) benefit |
|
0
|
0
|
0
|
0
|
| Equity in earnings of investment |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) |
|
0
|
0
|
0
|
0
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
0
|
0
|
| Consolidation Elimination Entries [Member] | Electric [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
(10)
|
(28)
|
(18)
|
(76)
|
| Consolidation Elimination Entries [Member] | Gas [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
2,195
|
2,558
|
11,209
|
9,030
|
| Consolidation Elimination Entries [Member] | Non Regulated Energy [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
11,576
|
11,121
|
22,994
|
22,225
|
| Consolidation Elimination Entries [Member] | Transmission Investment [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
0
|
0
|
0
|
0
|
| Consolidation Elimination Entries [Member] | Total Reportable Segments |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
13,761
|
13,651
|
34,185
|
31,179
|
| Consolidation Elimination Entries [Member] | All Others [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
0
|
0
|
0
|
0
|
| MGE [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
161,195
|
159,452
|
403,898
|
378,422
|
| Depreciation and amortization |
|
(28,939)
|
(28,354)
|
(57,028)
|
(56,032)
|
| Income tax (provision) benefit |
|
(3,079)
|
(2,229)
|
(7,709)
|
(7,569)
|
| Net Income (Loss) Attributable to Noncontrolling Interest |
|
5,729
|
5,714
|
11,335
|
11,313
|
| Net Income (Loss) |
|
22,483
|
18,761
|
62,590
|
52,965
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
$ 210,906
|
111,753
|
| Number of Reportable Segments | Segment |
|
|
|
3
|
|
| MGE [Member] | Electric [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
131,380
|
129,313
|
$ 262,760
|
254,767
|
| MGE [Member] | Gas [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
29,601
|
29,925
|
140,864
|
123,406
|
| MGE [Member] | Non Regulated Energy [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
214
|
214
|
274
|
249
|
| MGE [Member] | Operating Segments [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
161,195
|
159,452
|
403,898
|
378,422
|
| Fuel and purchased power |
|
(18,720)
|
(21,854)
|
(41,496)
|
(43,801)
|
| Purchased gas costs |
|
(9,285)
|
(11,313)
|
(80,108)
|
(65,277)
|
| Depreciation and amortization |
|
(28,939)
|
(28,354)
|
(57,028)
|
(56,032)
|
| Interest expense |
|
(11,236)
|
(9,142)
|
(22,374)
|
(18,304)
|
| Other segment items |
[2] |
(61,724)
|
(62,085)
|
(121,258)
|
(123,161)
|
| Income tax (provision) benefit |
|
(3,079)
|
(2,229)
|
(7,709)
|
(7,569)
|
| Net Income (Loss) Attributable to Noncontrolling Interest |
|
(5,729)
|
(5,714)
|
(11,335)
|
(11,313)
|
| Net Income (Loss) |
|
22,483
|
18,761
|
62,590
|
52,965
|
| MGE [Member] | Operating Segments [Member] | Electric [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
131,370
|
129,285
|
262,742
|
254,691
|
| Fuel and purchased power |
|
(19,509)
|
(22,524)
|
(43,582)
|
(45,630)
|
| Purchased gas costs |
|
0
|
0
|
0
|
0
|
| Depreciation and amortization |
|
(21,959)
|
(22,094)
|
(43,213)
|
(43,629)
|
| Interest expense |
|
(8,168)
|
(6,485)
|
(16,247)
|
(12,978)
|
| Other segment items |
[2] |
(57,877)
|
(58,130)
|
(113,151)
|
(114,109)
|
| Income tax (provision) benefit |
|
(1,237)
|
(472)
|
1,744
|
1,430
|
| Net Income (Loss) Attributable to Noncontrolling Interest |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) |
|
22,620
|
19,580
|
48,293
|
39,775
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
174,157
|
83,034
|
| MGE [Member] | Operating Segments [Member] | Gas [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
31,796
|
32,483
|
152,073
|
132,436
|
| Fuel and purchased power |
|
0
|
0
|
0
|
0
|
| Purchased gas costs |
|
(10,702)
|
(13,211)
|
(89,256)
|
(72,501)
|
| Depreciation and amortization |
|
(4,999)
|
(4,347)
|
(9,864)
|
(8,579)
|
| Interest expense |
|
(2,250)
|
(1,768)
|
(4,473)
|
(3,531)
|
| Other segment items |
[2] |
(15,372)
|
(15,015)
|
(30,977)
|
(31,111)
|
| Income tax (provision) benefit |
|
599
|
561
|
(4,664)
|
(4,426)
|
| Net Income (Loss) Attributable to Noncontrolling Interest |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) |
|
(928)
|
(1,297)
|
12,839
|
12,288
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
28,308
|
22,975
|
| MGE [Member] | Operating Segments [Member] | Non Regulated Energy [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
11,790
|
11,335
|
23,268
|
22,474
|
| Fuel and purchased power |
|
0
|
0
|
0
|
0
|
| Purchased gas costs |
|
0
|
0
|
0
|
0
|
| Depreciation and amortization |
|
(1,981)
|
(1,913)
|
(3,951)
|
(3,824)
|
| Interest expense |
|
(818)
|
(889)
|
(1,654)
|
(1,795)
|
| Other segment items |
[2] |
(30)
|
(23)
|
(81)
|
(67)
|
| Income tax (provision) benefit |
|
(2,441)
|
(2,318)
|
(4,789)
|
(4,573)
|
| Net Income (Loss) Attributable to Noncontrolling Interest |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) |
|
6,520
|
6,192
|
12,793
|
12,215
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
8,441
|
5,744
|
| MGE [Member] | Operating Segments [Member] | Total Reportable Segments |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
174,956
|
173,103
|
438,083
|
409,601
|
| Fuel and purchased power |
|
(19,509)
|
(22,524)
|
(43,582)
|
(45,630)
|
| Purchased gas costs |
|
(10,702)
|
(13,211)
|
(89,256)
|
(72,501)
|
| Depreciation and amortization |
|
(28,939)
|
(28,354)
|
(57,028)
|
(56,032)
|
| Interest expense |
|
(11,236)
|
(9,142)
|
(22,374)
|
(18,304)
|
| Other segment items |
[2] |
(73,279)
|
(73,168)
|
(144,209)
|
(145,287)
|
| Income tax (provision) benefit |
|
(3,079)
|
(2,229)
|
(7,709)
|
(7,569)
|
| Net Income (Loss) Attributable to Noncontrolling Interest |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) |
|
28,212
|
24,475
|
73,925
|
64,278
|
| MGE [Member] | Consolidation Elimination Entries [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
(13,761)
|
(13,651)
|
(34,185)
|
(31,179)
|
| Fuel and purchased power |
|
789
|
670
|
2,086
|
1,829
|
| Purchased gas costs |
|
1,417
|
1,898
|
9,148
|
7,224
|
| Depreciation and amortization |
|
0
|
0
|
0
|
0
|
| Interest expense |
|
0
|
0
|
0
|
0
|
| Other segment items |
[2] |
11,555
|
11,083
|
22,951
|
22,126
|
| Income tax (provision) benefit |
|
0
|
0
|
0
|
0
|
| Net Income (Loss) Attributable to Noncontrolling Interest |
|
(5,729)
|
(5,714)
|
(11,335)
|
(11,313)
|
| Net Income (Loss) |
|
(5,729)
|
(5,714)
|
(11,335)
|
(11,313)
|
| Segment Reporting Information Assets And Capital Expenditures [Abstract] |
|
|
|
|
|
| Segment Reporting, Long-Lived Asset, Expenditure for Addition |
|
|
|
0
|
0
|
| MGE [Member] | Consolidation Elimination Entries [Member] | Electric [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
(10)
|
(28)
|
(18)
|
(76)
|
| MGE [Member] | Consolidation Elimination Entries [Member] | Gas [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
2,195
|
2,558
|
11,209
|
9,030
|
| MGE [Member] | Consolidation Elimination Entries [Member] | Non Regulated Energy [Member] |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
11,576
|
11,121
|
22,994
|
22,225
|
| MGE [Member] | Consolidation Elimination Entries [Member] | Total Reportable Segments |
|
|
|
|
|
| Segment Reporting [Line Items] |
|
|
|
|
|
| Operating revenues |
|
$ 13,761
|
$ 13,651
|
$ 34,185
|
$ 31,179
|
|
|