Equity and Financing Arrangements	6 Months Ended
Jun. 30, 2018
Equity and Financing Arrangements Disclosure [Abstract]
Equity and Financing Arrangements	Equity and Financing Arrangements - MGE Energy. a. Common Stock. MGE Energy sells shares of its common stock through its Stock Plan. Those shares may be newly issued shares or shares that MGE Energy has purchased in the open market for resale to participants in the Stock Plan. All sales under the Stock Plan are covered by a shelf registration statement that MGE Energy filed with the SEC. For both the three and six months ended June 30, 2018 and 2017, MGE Energy did not issue any new shares of common stock under the Stock Plan. b. Dilutive Shares Calculation. MGE Energy does not have any stock option or stock award programs or any dilutive securities. c. Long-term Debt - MGE Energy and MGE. In July 2018, MGE issued $20 million of new long-term unsecured debt carrying an interest rate of 4.24% per annum over its 35-year term and $20 million of new long-term unsecured debt carrying an interest rate of 4.34% per annum over its 40-year term. MGE has also committed to issue $60 million of new long-term unsecured debt that will carry an interest rate of 4.19% per annum over its 30-year life with funding expected to occur in September 2018. The proceeds of these debt financings will be used to assist with capital expenditures, such as the Saratoga Wind Farm, and to refinance $20 million of long-term debt at its maturity in September 2018. The covenants of this debt are substantially consistent with MGE's existing unsecured long-term debt. In accordance with applicable accounting guidance, MGE has classified the $20 million of maturing unsecured debt as long-term debt on the consolidated balance sheets for the quarter ended June 30, 2018.

Equity and Financing Arrangements

6 Months Ended

Jun. 30, 2018

Equity and Financing Arrangements Disclosure [Abstract]

Equity and Financing Arrangements - MGE Energy.

a. Common Stock.

MGE Energy sells shares of its common stock through its Stock Plan. Those shares may be newly issued shares or shares that MGE Energy has purchased in the open market for resale to participants in the Stock Plan. All sales under the Stock Plan are covered by a shelf registration statement that MGE Energy filed with the SEC. For both the three and six months ended June 30, 2018 and 2017, MGE Energy did not issue any new shares of common stock under the Stock Plan.

b. Dilutive Shares Calculation.

MGE Energy does not have any stock option or stock award programs or any dilutive securities.

c. Long-term Debt - MGE Energy and MGE.

In July 2018, MGE issued $20 million of new long-term unsecured debt carrying an interest rate of 4.24% per annum over its 35-year term and $20 million of new long-term unsecured debt carrying an interest rate of 4.34% per annum over its 40-year term. MGE has also committed to issue $60 million of new long-term unsecured debt that will carry an interest rate of 4.19% per annum over its 30-year life with funding expected to occur in September 2018. The proceeds of these debt financings will be used to assist with capital expenditures, such as the Saratoga Wind Farm, and to refinance $20 million of long-term debt at its maturity in September 2018. The covenants of this debt are substantially consistent with MGE's existing unsecured long-term debt. In accordance with applicable accounting guidance, MGE has classified the $20 million of maturing unsecured debt as long-term debt on the consolidated balance sheets for the quarter ended June 30, 2018.