Fair Value of Financial Instruments (Details-4) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance,		$ (1,726)	$ (3,740)	$ (2,604)	$ (866)
Realized and unrealized gains (losses):
Included in regulatory assets		294	848	1,172	(2,026)
Included in earnings	[1]	(1,330)	(903)	(3,855)	(5,574)
Settlements		1,330	903	3,855	5,574
Ending balance,		$ (1,432)	$ (2,892)	$ (1,432)	$ (2,892)

[1] MGE's exchange-traded derivative contracts, over-the-counter party transactions, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.