Minimum threshold percentage that MGEE must hold of the outstanding voting equity interest in MGE.

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+ References

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Amount of increase (decrease) to net income used for calculating diluted earnings per share (EPS), resulting from the assumed exercise stock options, restrictive stock units (RSUs), convertible preferred stock of an employee stock ownership plan (ESOP), and other dilutive convertible securities.

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Indebtedness divided by net capital.

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Equity and Financing Arrangements (Details) - USD ($)	3 Months Ended	9 Months Ended
Equity and Financing Arrangements (Details) - USD ($)	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Apr. 20, 2020
Common Stock [Abstract]
Common stock issued during period		1,500,000
Common stock issued during period under the stock plan	0	0
Issuance of common stock, net		$ 79,635,000	$ 0
Dilutive Shares Calculation [Abstract]
Dilutive securities		0
Future Debt Issuance, 2.05%, 2027 Series, Industrial Development Revenue Bonds
Debt Instrument [Line Items]
Face amount				$ 19,300,000
Interest rate				2.05%
Debt covenant, MGEE's outstanding voting equity interest in MGE				100.00%
Future Debt Issuance, 2.05%, 2027 Series, Industrial Development Revenue Bonds \| Minimum [Member]
Debt Instrument [Line Items]
Debt covenant, ownership interest by outside party resulting in repurchase of notes at par value				30.00%
Future Debt Issuance, 2.05%, 2027 Series, Industrial Development Revenue Bonds \| Maximum [Member]
Debt Instrument [Line Items]
Debt to total capitalization ratio				0.65
3.45%, 2027 Series, Industrial Development Revenue Bonds
Debt Instrument [Line Items]
Long-term debt, gross		$ 19,300,000