Fair Value of Financial Instruments (Details-1) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Liabilities:
Unamortized discount and debt issuance costs		$ 4,349	$ 4,146
Carrying Amount [Member]
Assets:
Cash and cash equivalents		17,438	44,738
Liabilities:
Short-term debt - commercial paper		5,500	52,500
Long-Term debt	[1]	623,449	528,220
Fair Value [Member]
Assets:
Cash and cash equivalents		17,438	44,738
Liabilities:
Short-term debt - commercial paper		5,500	52,500
Long-Term debt	[1]	729,914	639,271
MGE [Member]
Liabilities:
Unamortized discount and debt issuance costs		4,300	4,100
MGE [Member] | Carrying Amount [Member]
Assets:
Cash and cash equivalents		6,401	4,103
Liabilities:
Short-term debt - commercial paper		5,500	52,500
Long-Term debt	[1]	623,449	528,220
MGE [Member] | Fair Value [Member]
Assets:
Cash and cash equivalents		6,401	4,103
Liabilities:
Short-term debt - commercial paper		5,500	52,500
Long-Term debt	[1]	$ 729,914	$ 639,271

[1] Includes long-term debt due within one year. Excludes debt issuance costs and unamortized discount of $4.3 million and $4.1 million as of December 31, 2021 and 2020, respectively.