Derivative and Hedging Instruments (Details-1) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2025 USD ($) Dth1 MWh MW	Dec. 31, 2024 USD ($) Dth1 MWh MW
Derivative fair values [Abstract]
Collateral posted against derivative positions		$ 2,000
Derivative, right to reclaim collateral			$ 100
Commodity Contracts And Financial Transimission Rights [Member]
Derivative fair values [Abstract]
Derivative, Fair Value, Net		$ 1,900	$ 100
Commodity Contract [Member]
Gross Notional Volume of Open Derivatives [Abstract]
Notional amount, energy measures (in MWh) | MWh		320,880	307,640
Notional amount, decatherm measure (in Dth) | Dth1		2,642,500	6,285,000
Derivative fair values [Abstract]
Derivative Asset, Fair Value, Gross Asset		$ 2,297	$ 1,213
Derivative Liability, Fair Value, Gross Liability		304	1,261
Collateral posted against derivative positions		0	0
Derivative, right to reclaim collateral		(1,993)	48
Commodity Contract [Member] | Other Current Assets/Liabilities
Derivative fair values [Abstract]
Derivative Asset, Fair Value, Gross Asset	[1]	1,995
Derivative Liability, Fair Value, Gross Liability	[1]	261
Commodity Contract [Member] | Other Deferred Charges [Member]
Derivative fair values [Abstract]
Derivative Asset, Fair Value, Gross Asset	[1]	302
Derivative Liability, Fair Value, Gross Liability	[1]	43
Commodity Contract [Member] | Other Current Liabilities [Member]
Derivative fair values [Abstract]
Derivative Asset, Fair Value, Gross Asset	[1]		927
Derivative Liability, Fair Value, Gross Liability	[1]		1,121
Commodity Contract [Member] | Other Deferred Liabilities and Other [Member]
Derivative fair values [Abstract]
Derivative Asset, Fair Value, Gross Asset	[1]		286
Derivative Liability, Fair Value, Gross Liability	[1]		140
Commodity Contract [Member] | Cash Flow Hedging [Member]
Derivative fair values [Abstract]
Derivative, right to reclaim collateral (receivable)			$ 100
Collateral posted against derivative positions		$ 2,000
Energy Related Commodity Contract [Member] | Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Maximum term of derivative hedging contract		4 years
Financial Transmission Rights [Member]
Gross Notional Volume of Open Derivatives [Abstract]
Notional amount, power measure (in MW) | MW		787	2,131
Derivative fair values [Abstract]
Derivative Asset, Fair Value, Gross Asset			$ 108
Derivative Liability, Fair Value, Gross Liability		$ 133
Collateral posted against derivative positions			0
Derivative, right to reclaim collateral		133
Financial Transmission Rights [Member] | Other Current Assets/Liabilities
Derivative fair values [Abstract]
Derivative Asset, Fair Value, Gross Asset			108
Derivative Liability, Fair Value, Gross Liability			$ 0
Financial Transmission Rights [Member] | Other Current Liabilities [Member]
Derivative fair values [Abstract]
Derivative Asset, Fair Value, Gross Asset		0
Derivative Liability, Fair Value, Gross Liability		$ 133

[1] As of March 31, 2025, MGE received collateral of $2.0 million from counterparties under a master netting agreement for outstanding exchange traded derivative positions on the consolidated balance sheets. As of December 31, 2024, collateral of less than $0.1 million was posted against and netted with derivative liability positions. The fair value of the derivatives disclosed in this table has not been adjusted for the collateral posted.