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v3.19.3.a.u2

Summary of Significant Accounting Policies (Tables) | 12 Months Ended
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Dec. 31, 2019
Accounting Policies [Abstract] |
Cash, Cash Equivalents, and Restricted Cash | The following table presents the components of total cash, cash equivalents, and restricted cash on the consolidated balance sheets.
| (In thousands) |  | MGE Energy |  | MGE |
| As of December 31, |  | 2019 |  | 2018 |  | 2019 |  | 2018 |
| Cash and cash equivalents | $ | 23,481 | $ | 83,102 | $ | 3,196 | $ | 4,843 |
| Restricted cash |  | 619 |  | 634 |  | 619 |  | 634 |
| Receivable - margin account |  | 1,714 |  | 1,193 |  | 1,714 |  | 1,193 |
| Cash, cash equivalents, and restricted cash | $ | 25,814 | $ | 84,929 | $ | 5,529 | $ | 6,670 |
Schedule of Remaining Contractual Maturities for Chattel Paper Agreements | As of December 31, 2019, the remaining contractual maturities of the chattel paper agreements were as follows:
| (In thousands) |  | 2020 |  | 2021 |  | 2022 |  | 2023 |  | 2024 |  | Thereafter |
| Repurchase-to-Maturity Transactions: |  |  |  |  |  |  |  |  |  |  |  |  |
| Loans | $ | 280 | $ | 267 | $ | 250 | $ | 181 | $ | 70 | $ | 119 |
Straight-Line Depreciation Rates | Provisions at composite straight-line depreciation rates approximate the following percentages for the cost of depreciable property:
|  | 2019 |  |  | 2018 |  |  | 2017 |  |  |
| Electric(a) | 3.6 | % |  | 2.9 | % |  | 3.0 | % |  |
| Gas | 2.1 | % |  | 2.1 | % |  | 2.1 | % |  |
| Nonregulated | 2.3 | % |  | 2.3 | % |  | 2.3 | % |  |
(a) In the December 2018 rate settlement, the PSCW approved new depreciation rates for Columbia effective January 1, 2019.

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- Definition Tabular disclosure of the nature and risks of short-term collateralized financing obtained through repurchase agreements, securities lending transactions and repurchase-to-maturity transactions, accounted for as secured borrowings. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=109249958&loc=SL34722452-111729 + Details
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