Pension Plans and Other Postretirement Benefits (Details-2) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Deferred Pension and Other Postretirement Benefit Plan Costs Recovered [Abstract]
Deferred (recognized) pension and OPEB costs		$ (4,300)	$ (900)	$ 6,200
Deferred savings from 2021 employee benefit plan costs		8,100
Pension Benefits [Member]
Components of Net Periodic Benefit Cost
Service cost	[1]	5,730	5,296	4,692
Interest cost	[1]	9,109	12,210	14,302
Expected return on assets	[1]	(29,487)	(27,229)	(22,786)
Amortization of:
Transition obligation	[1]	0	0	0
Prior service (credit) cost	[1]	(124)	(114)	(117)
Actuarial loss	[1]	6,646	5,357	7,379
Net periodic benefit cost (credit)	[1]	(8,126)	(4,480)	3,470
Postretirement Benefits [Member]
Components of Net Periodic Benefit Cost
Service cost	[1]	1,448	1,264	1,110
Interest cost	[1]	1,549	2,278	2,893
Expected return on assets	[1]	(3,277)	(3,154)	(2,723)
Amortization of:
Transition obligation	[1]	(3)	(3)	(3)
Prior service (credit) cost	[1]	(1,518)	(2,669)	(2,669)
Actuarial loss	[1]	493	217	401
Net periodic benefit cost (credit)	[1]	$ (1,302)	$ (2,061)	$ (985)

[1] During 2019, MGE deferred approximately $6.2 million of pension and other postretirement costs. During 2021 and 2020, MGE collected approximately $4.3 million and $0.9 million, respectively, of pension and other postretirement costs, which reduced the amount deferred in prior years. The impact of the deferral has not been reflected in the table above. See Footnote 8 for further information. During the year ended December 30, 2021, MGE deferred $8.1 million of savings from 2021 employee benefit plan costs and recorded as a regulatory liability. The deferred savings has not been reflected in the table above. See Footnote 8 for additional information.