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Regulatory Assets and Liabilities (Tables) | 12 Months Ended
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Dec. 31, 2019
Regulatory Assets and Liabilities Disclosure [Abstract] |
Regulatory Assets and Liabilities | The following regulatory assets and liabilities are reflected in MGE's consolidated balance sheets as of December 31:
| (In thousands) |  |  | 2019 |  |  | 2018 |
| Regulatory Assets |  |  |  |  |  |  |
| Asset retirement obligation |  | $ | 10,756 |  | $ | 9,199 |
| Debt related costs |  |  | 8,885 |  |  | 9,288 |
| Deferred pension and other postretirement costs |  |  | 6,216 |  |  | - |
| Derivatives |  |  | 26,875 |  |  | 31,830 |
| Leases |  |  | 2,400 |  |  | 59 |
| Tax recovery related to AFUDC equity |  |  | 7,060 |  |  | 6,482 |
| Unfunded pension and other postretirement liability |  |  | 83,214 |  |  | 96,030 |
| Other |  |  | 340 |  |  | 2,013 |
| Total Regulatory Assets |  | $ | 145,746 |  | $ | 154,901 |
| Regulatory Liabilities |  |  |  |  |  |  |
| Deferred fuel savings |  | $ | 1,794 |  | $ | 9,504 |
| Elm Road |  |  | 2,322 |  |  | 2,515 |
| Income taxes |  |  | 129,528 |  |  | 135,449 |
| Non-ARO removal costs |  |  | 26,543 |  |  | 19,891 |
| Pension and other postretirement service costs |  |  | 4,499 |  |  | 3,669 |
| Purchased gas adjustment |  |  | 1,864 |  |  | 1,186 |
| Renewable energy credits |  |  | 558 |  |  | 700 |
| Transmission |  |  | 6,019 |  |  | 5,476 |
| Other |  |  | 1,066 |  |  | 1,074 |
| Total Regulatory Liabilities |  | $ | 174,193 |  | $ | 179,464 |

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- Definition Tabular disclosure of regulatory assets and liabilities. Assets are created when regulatory agencies permit public utilities to defer certain costs included in rate-setting to the balance sheet. Liabillities are the result of rate actions a regulator can impose on a regulated enterprise resulting in a regulatory liability. + References No definition available. + Details
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- References No definition available. + Details
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