Share-Based Compensation	9 Months Ended
Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation - MGE Energy and MGE. Under MGE Energy's Director Incentive Plan and its Performance Unit Plan, non-employee directors and eligible employees, respectively, may receive performance units that entitle the holder to receive a cash payment equal to the value of a designated number of shares of MGE Energy's common stock, plus dividend equivalent payments thereon, at the end of the performance period set in the award. In 2019, 5,175 units were granted under the Director Incentive Plan and are subject to a three-year graded vesting schedule, and 17,022 units were granted under the Performance Unit Plan and are subject to a five-year graded vesting schedule. On the grant date, the cost of the director or employee services received in exchange for a performance unit award is measured based on the current market value of MGE Energy common stock. The fair value of the awards is remeasured quarterly, including as of September 30, 2019, as required by applicable accounting standards. Changes in fair value as well as the original grant are recognized as compensation cost. Since this amount is remeasured throughout the vesting period, the compensation cost is subject to variability. For nonretirement eligible employees under the Performance Unit Plan, stock-based compensation costs are accrued and recognized using the graded vesting method. Compensation cost for retirement eligible employees or employees that will become retirement eligible during the vesting schedule are recognized on an abridged horizon as retirement eligibility accelerates vesting. During the three and nine months ended September 30, 2019, MGE recorded $0.9 million and $2.8 million, respectively, in compensation expense as a result of awards under the plans compared to $0.3 million and $1.3 million for the comparable periods in 2018. In January 2019, cash payments of $1.5 million were distributed relating to awards that were granted in a prior year under the plans. No forfeitures of units occurred during the three and nine months ended September 30, 2019 and 2018. As of September 30, 2019, $6.2 million of outstanding awards are vested. Of this amount, no cash settlements have occurred as cash payments are only made at the end of the period covered by the awards.

Share-Based Compensation

9 Months Ended

Sep. 30, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-Based Compensation - MGE Energy and MGE.

Under MGE Energy's Director Incentive Plan and its Performance Unit Plan, non-employee directors and eligible employees, respectively, may receive performance units that entitle the holder to receive a cash

payment equal to the value of a designated number of shares of MGE Energy's common stock, plus dividend equivalent payments thereon, at the end of the performance period set in the award.

In 2019, 5,175 units were granted under the Director Incentive Plan and are subject to a three-year graded vesting schedule, and 17,022 units were granted under the Performance Unit Plan and are subject to a five-year graded vesting schedule. On the grant date, the cost of the director or employee services received in exchange for a performance unit award is measured based on the current market value of MGE Energy common stock. The fair value of the awards is remeasured quarterly, including as of September 30, 2019, as required by applicable accounting standards. Changes in fair value as well as the original grant are recognized as compensation cost. Since this amount is remeasured throughout the vesting period, the compensation cost is subject to variability.

For nonretirement eligible employees under the Performance Unit Plan, stock-based compensation costs are accrued and recognized using the graded vesting method. Compensation cost for retirement eligible employees or employees that will become retirement eligible during the vesting schedule are recognized on an abridged horizon as retirement eligibility accelerates vesting.

During the three and nine months ended September 30, 2019, MGE recorded $0.9 million and $2.8 million, respectively, in compensation expense as a result of awards under the plans compared to $0.3 million and $1.3 million for the comparable periods in 2018. In January 2019, cash payments of $1.5 million were distributed relating to awards that were granted in a prior year under the plans. No forfeitures of units occurred during the three and nine months ended September 30, 2019 and 2018. As of September 30, 2019, $6.2 million of outstanding awards are vested. Of this amount, no cash settlements have occurred as cash payments are only made at the end of the period covered by the awards.