$MGEE
MGE ENERGY INC Stock $mgee

$mgee Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-K Financial Statement

#000116172821000013 Filed on February 24, 2021

Income Statement

Concept	2020 Q4	2019 Q4	2019 Q3
Revenue	$136.5M	$140.9M	$138.2M
YoY Change	-3.14%	0.62%	0.29%
Cost Of Revenue	$33.60M	$35.00M	$12.20M
YoY Change	-4.0%	-9.33%	-31.84%
Gross Profit	$102.9M	$105.9M	$126.0M
YoY Change	-2.83%	4.33%	5.09%
Gross Profit Margin	75.38%	75.14%	91.17%
Selling, General & Admin		$100.0K	$0.00
YoY Change
% of Gross Profit		0.09%	0.0%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$19.00M	$18.20M	$18.20M
YoY Change	4.4%	24.66%	27.27%
% of Gross Profit	18.46%	17.19%	14.44%
Operating Expenses	$84.20M	$84.10M	$87.30M
YoY Change	0.12%	8.52%	8.99%
Operating Profit	$18.71M	$21.88M	$38.74M
YoY Change	-14.47%	-8.81%	-2.66%
Interest Expense	-$5.800M	-$5.800M	-$5.800M
YoY Change	0.0%	13.73%	16.0%
% of Operating Profit	-31.0%	-26.51%	-14.97%
Other Income/Expense, Net	$6.200M	$3.700M	$5.204M
YoY Change	67.57%	19.35%	20.18%
Pretax Income	$19.20M	$19.80M	$38.11M
YoY Change	-3.03%	-10.0%	-2.54%
Income Tax	$3.370M	$3.116M	$7.454M
% Of Pretax Income	17.55%	15.74%	19.56%
Net Earnings	$15.80M	$16.66M	$30.66M
YoY Change	-5.2%	1.84%	3.9%
Net Earnings / Revenue	11.57%	11.82%	22.18%
Basic Earnings Per Share
Diluted Earnings Per Share	$436.5K	$481.3K	$884.7K
COMMON SHARES
Basic Shares Outstanding	36.16M shares	34.67M shares	34.67M shares
Diluted Shares Outstanding

Balance Sheet

Concept	2020 Q4	2019 Q4	2019 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments	$44.70M	$23.50M	$61.10M
YoY Change	90.21%	-71.72%	-54.37%
Cash & Equivalents	$44.74M	$23.48M	$61.11M
Short-Term Investments
Other Short-Term Assets	$11.39M	$10.23M	$8.631M
YoY Change	11.35%	19.09%	-83.43%
Inventory	$47.30M	$45.30M	$47.80M
Prepaid Expenses
Receivables	$41.38M	$40.48M	$35.81M
Other Receivables	$7.300M	$7.940M	$7.867M
Total Short-Term Assets	$209.5M	$181.6M	$204.4M
YoY Change	15.35%	-24.49%	-27.18%
LONG-TERM ASSETS
Property, Plant & Equipment	$1.769B	$1.643B	$1.613B
YoY Change	7.71%	8.83%	10.52%
Goodwill
YoY Change
Intangibles
YoY Change
Long-Term Investments	$74.46M	$71.65M	$85.70M
YoY Change	3.93%	8.0%	16.76%
Other Assets	$22.26M	$19.09M	$17.10M
YoY Change	16.58%	52.89%	95.85%
Total Long-Term Assets	$2.044B	$1.900B	$1.863B
YoY Change	7.58%	8.69%	9.98%
TOTAL ASSETS
Total Short-Term Assets	$209.5M	$181.6M	$204.4M
Total Long-Term Assets	$2.044B	$1.900B	$1.863B
Total Assets	$2.254B	$2.082B	$2.067B
YoY Change	8.26%	4.68%	4.69%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$54.64M	$55.16M	$39.14M
YoY Change	-0.94%	19.5%	-22.25%
Accrued Expenses	$21.20M	$20.20M	$16.80M
YoY Change	4.95%	-0.98%	2.44%
Deferred Revenue
YoY Change
Short-Term Debt	$52.50M	$0.00	$54.50M
YoY Change		-100.0%
Long-Term Debt Due	$4.771M	$19.66M	$4.632M
YoY Change	-75.73%	331.78%	2.32%
Total Short-Term Liabilities	$190.9M	$128.8M	$152.1M
YoY Change	48.21%	6.79%	54.38%
LONG-TERM LIABILITIES
Long-Term Debt	$519.3M	$523.7M	$490.2M
YoY Change	-0.85%	6.16%	-0.86%
Other Long-Term Liabilities	$72.21M	$63.01M	$70.69M
YoY Change	14.6%	-5.05%	-1.91%
Total Long-Term Liabilities	$567.4M	$573.4M	$573.5M
YoY Change	-1.05%	2.76%	0.72%
TOTAL LIABILITIES
Total Short-Term Liabilities	$190.9M	$128.8M	$152.1M
Total Long-Term Liabilities	$567.4M	$573.4M	$573.5M
Total Liabilities	$758.3M	$702.2M	$725.6M
YoY Change	7.99%	3.48%	8.63%
SHAREHOLDERS EQUITY
Retained Earnings	$545.4M	$504.7M
YoY Change	8.06%	8.38%
Common Stock	$36.16M	$34.67M
YoY Change	4.31%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$976.0M	$855.7M	$851.2M
YoY Change
Total Liabilities & Shareholders Equity	$2.254B	$2.082B	$2.067B
YoY Change	8.26%	4.68%	4.69%

Cashflow Statement

Concept	2020 Q4	2019 Q4	2019 Q3
OPERATING ACTIVITIES
Net Income	$15.80M	$16.66M	$30.66M
YoY Change	-5.2%	1.84%	3.9%
Depreciation, Depletion And Amortization	$19.00M	$18.20M	$18.20M
YoY Change	4.4%	24.66%	27.27%
Cash From Operating Activities	$36.40M	$18.80M	$25.80M
YoY Change	93.62%	28.77%	-44.87%
INVESTING ACTIVITIES
Capital Expenditures	-$64.00M	-$35.60M	-$49.30M
YoY Change	79.78%	-43.67%	1.44%
Acquisitions
YoY Change
Other Investing Activities	-$2.000M	-$2.200M	-$2.600M
YoY Change	-9.09%	29.41%	52.94%
Cash From Investing Activities	-$66.00M	-$37.90M	-$51.90M
YoY Change	74.14%	-41.6%	3.18%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	22.60M	-18.30M	17.50M
YoY Change	-223.5%	-9250.0%	-54.31%
NET CHANGE
Cash From Operating Activities	36.40M	18.80M	25.80M
Cash From Investing Activities	-66.00M	-37.90M	-51.90M
Cash From Financing Activities	22.60M	-18.30M	17.50M
Net Change In Cash	-7.000M	-37.40M	-8.600M
YoY Change	-81.28%	-25.35%	-124.71%
FREE CASH FLOW
Cash From Operating Activities	$36.40M	$18.80M	$25.80M
Capital Expenditures	-$64.00M	-$35.60M	-$49.30M
Free Cash Flow	$100.4M	$54.40M	$75.10M
YoY Change	84.56%	-30.08%	-21.28%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2020	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	6296000	USD
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	5787000	USD
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	1290000	USD
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	75000000	shares
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	2820000	USD
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	75000000	shares
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	438000	USD
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	36163000	shares
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	34668000	shares
CY2020Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	36163000	shares
CY2020	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2019	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2018	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2020Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	4146000	USD
CY2019Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	4479000	USD
CY2018	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.32
CY2019Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P39Y
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P15Y
CY2020	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2020	dei	Entity Central Index Key EntityCentralIndexKey	0001161728
CY2020	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2020	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2020	dei	Entity Small Business EntitySmallBusiness	false
CY2020	dei	Entity Shell Company EntityShellCompany	false
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	24007000	USD
CY2020Q4	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	136509000	USD
CY2020Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	5013000	USD
CY2020	dei	Document Transition Report DocumentTransitionReport	false
CY2020	dei	Document Annual Report DocumentAnnualReport	true
CY2019Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	0.1	USD
CY2020Q4	us-gaap	Defined Benefit Plan Expected Future Employer Contributions Next Fiscal Year DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear	0	USD
CY2019Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2020Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2020	dei	Amendment Flag AmendmentFlag	false
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	79635000	USD
CY2019Q4	mgee	Variable Interest Entity Purchase Power Agreement Plant Capacity Other VariableInterestEntityPurchasePowerAgreementPlantCapacityOther	13	MW
CY2019	mgee	Stock Issued During Period Under The Stock Plan StockIssuedDuringPeriodUnderTheStockPlan	0	shares
CY2020	mgee	Lcfrauditorattestationflag Lcfrauditorattestationflag	true
CY2019	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	5100000	USD
CY2020Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P37Y
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P34Y
CY2020	dei	Document Type DocumentType	10-K
CY2020	dei	Document Period End Date DocumentPeriodEndDate	2020-12-31
CY2020	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
CY2020	dei	Entity File Number EntityFileNumber	000-49965
CY2020	dei	Entity Registrant Name EntityRegistrantName	MGE Energy, Inc.
CY2020	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	WI
CY2020	dei	Entity Address City Or Town EntityAddressCityOrTown	Madison
CY2020	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	53788
CY2020	dei	City Area Code CityAreaCode	608
CY2020	dei	Local Phone Number LocalPhoneNumber	252-7000
CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	39-2040501
CY2020	dei	Entity Address Address Line1 EntityAddressAddressLine1	133 S Blair Street
CY2020	dei	Entity Address State Or Province EntityAddressStateOrProvince	WI
CY2020	dei	Security12b Title Security12bTitle	Common Stock, $1 Par Value Per Share
CY2020	dei	Trading Symbol TradingSymbol	MGEE
CY2020	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2020	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2020	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2020	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2020	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2020Q2	dei	Entity Public Float EntityPublicFloat	2292032738	USD
CY2021Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	36163370	shares
CY2018	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	559768000	USD
CY2018	us-gaap	Utilities Operating Expense Depreciation And Amortization UtilitiesOperatingExpenseDepreciationAndAmortization	56412000	USD
CY2018	us-gaap	Operating Income Loss OperatingIncomeLoss	114207000	USD
CY2018	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	17055000	USD
CY2018	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-19609000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	111653000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	19423000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	19784000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	0	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	27434000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	92418000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	86874000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	84219000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	84219000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	92418000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	86874000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	84219000	USD
CY2018	us-gaap	Utilities Operating Expense Depreciation And Amortization UtilitiesOperatingExpenseDepreciationAndAmortization	56412000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	10363000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	7212000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	3749000	USD
CY2020	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	1415000	USD
CY2019	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	1615000	USD
CY2018	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	1366000	USD
CY2020	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	-3716000	USD
CY2019	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	-3813000	USD
CY2018	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	-2002000	USD
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	10221000	USD
CY2019	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	9889000	USD
CY2018	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	8821000	USD
CY2020	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	2750000	USD
CY2019	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-163000	USD
CY2018	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	814000	USD
CY2020	us-gaap	Increase Decrease In Accounts And Other Receivables IncreaseDecreaseInAccountsAndOtherReceivables	3838000	USD
CY2019	us-gaap	Increase Decrease In Accounts And Other Receivables IncreaseDecreaseInAccountsAndOtherReceivables	1285000	USD
CY2018	us-gaap	Increase Decrease In Accounts And Other Receivables IncreaseDecreaseInAccountsAndOtherReceivables	2235000	USD
CY2020	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	842000	USD
CY2019	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	3420000	USD
CY2018	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-2724000	USD
CY2020	us-gaap	Increase Decrease In Unbilled Receivables IncreaseDecreaseInUnbilledReceivables	1613000	USD
CY2019	us-gaap	Increase Decrease In Unbilled Receivables IncreaseDecreaseInUnbilledReceivables	-2345000	USD
CY2018	us-gaap	Increase Decrease In Unbilled Receivables IncreaseDecreaseInUnbilledReceivables	-3157000	USD
CY2020	us-gaap	Increase Decrease In Prepaid Taxes IncreaseDecreaseInPrepaidTaxes	-1713000	USD
CY2019	us-gaap	Increase Decrease In Prepaid Taxes IncreaseDecreaseInPrepaidTaxes	677000	USD
CY2018	us-gaap	Increase Decrease In Prepaid Taxes IncreaseDecreaseInPrepaidTaxes	-10320000	USD
CY2020	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	1057000	USD
CY2019	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	-29000	USD
CY2018	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	-251000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	14353000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-7432000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-4855000	USD
CY2020	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	-5635000	USD
CY2019	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	-10264000	USD
CY2018	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	11957000	USD
CY2020	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	8998000	USD
CY2019	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	7347000	USD
CY2018	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	6958000	USD
CY2020	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	6296000	USD
CY2019	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	5714000	USD
CY2018	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	5584000	USD
CY2020	us-gaap	Increase Decrease In Other Noncurrent Assets And Liabilities Net IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	-4963000	USD
CY2019	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-13000000	USD
CY2018	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	9000000	USD
CY2020	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-1553000	USD
CY2019	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-1838000	USD
CY2019	us-gaap	Increase Decrease In Other Noncurrent Assets And Liabilities Net IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	4178000	USD
CY2018	us-gaap	Increase Decrease In Other Noncurrent Assets And Liabilities Net IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	3762000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	172443000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	130475000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	153040000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	203139000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	164036000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	212197000	USD
CY2020	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	5601000	USD
CY2019	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	7813000	USD
CY2018	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	5926000	USD
CY2020	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	1672000	USD
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	508000	USD
CY2018	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	205000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-210412000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-172357000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-218328000	USD
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	79635000	USD
CY2019	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	0	USD
CY2018	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	0	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	51729000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	47842000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	45762000	USD
CY2020	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	38959000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	4553000	USD
CY2018	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	24453000	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	19300000	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	50000000	USD
CY2018	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	100000000	USD
CY2020	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	52500000	USD
CY2018	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-662000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	59194000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-17233000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	38123000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	21225000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-59115000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-27165000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	25814000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	84929000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	112094000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	47039000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	25814000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	84929000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	23898000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	23171000	USD
CY2018	us-gaap	Interest Paid Net InterestPaidNet	20018000	USD
CY2020	us-gaap	Income Taxes Paid IncomeTaxesPaid	8127000	USD
CY2019	us-gaap	Income Taxes Paid IncomeTaxesPaid	14617000	USD
CY2018	us-gaap	Income Taxes Paid IncomeTaxesPaid	12597000	USD
CY2020	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	0	USD
CY2019Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	112484000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1769385000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1642683000	USD
CY2020Q4	us-gaap	Investments Investments	94676000	USD
CY2019Q4	us-gaap	Investments Investments	88492000	USD
CY2019	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	255000	USD
CY2018	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	59000	USD
CY2020	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	5719000	USD
CY2019	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	26697000	USD
CY2018	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	11129000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	44738000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	23481000	USD
CY2020Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	41384000	USD
CY2019Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	40482000	USD
CY2020Q4	us-gaap	Other Receivables Net Current OtherReceivablesNetCurrent	7300000	USD
CY2019Q4	us-gaap	Other Receivables Net Current OtherReceivablesNetCurrent	7940000	USD
CY2020Q4	us-gaap	Unbilled Receivables Current UnbilledReceivablesCurrent	27511000	USD
CY2019Q4	us-gaap	Unbilled Receivables Current UnbilledReceivablesCurrent	25899000	USD
CY2020Q4	us-gaap	Other Inventory Supplies OtherInventorySupplies	32513000	USD
CY2019Q4	us-gaap	Other Inventory Supplies OtherInventorySupplies	26287000	USD
CY2020Q4	us-gaap	Energy Related Inventory Other Fossil Fuel EnergyRelatedInventoryOtherFossilFuel	6356000	USD
CY2019Q4	us-gaap	Energy Related Inventory Other Fossil Fuel EnergyRelatedInventoryOtherFossilFuel	8358000	USD
CY2020Q4	us-gaap	Energy Related Inventory Gas Stored Underground EnergyRelatedInventoryGasStoredUnderground	8396000	USD
CY2019Q4	us-gaap	Energy Related Inventory Gas Stored Underground EnergyRelatedInventoryGasStoredUnderground	10637000	USD
CY2020Q4	us-gaap	Prepaid Taxes PrepaidTaxes	15179000	USD
CY2019Q4	us-gaap	Prepaid Taxes PrepaidTaxes	16892000	USD
CY2020Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	14748000	USD
CY2019Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	11432000	USD
CY2020Q4	us-gaap	Other Assets Current OtherAssetsCurrent	11394000	USD
CY2019Q4	us-gaap	Other Assets Current OtherAssetsCurrent	10233000	USD
CY2020Q4	us-gaap	Assets Current AssetsCurrent	209519000	USD
CY2019Q4	us-gaap	Assets Current AssetsCurrent	181641000	USD
CY2020Q4	us-gaap	Notes And Loans Receivable Net Noncurrent NotesAndLoansReceivableNetNoncurrent	1435000	USD
CY2019Q4	us-gaap	Notes And Loans Receivable Net Noncurrent NotesAndLoansReceivableNetNoncurrent	1811000	USD
CY2020Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	142504000	USD
CY2019Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	134314000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	13873000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	13630000	USD
CY2020Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	22259000	USD
CY2019Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	19093000	USD
CY2020Q4	mgee	Property Plant And Equipment Net Before Construction In Progress PropertyPlantAndEquipmentNetBeforeConstructionInProgress	1630286000	USD
CY2019Q4	mgee	Property Plant And Equipment Net Before Construction In Progress PropertyPlantAndEquipmentNetBeforeConstructionInProgress	1530199000	USD
CY2020Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	139099000	USD
CY2020Q4	us-gaap	Assets Assets	2253651000	USD
CY2020Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	72211000	USD
CY2019Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	63013000	USD
CY2019Q4	us-gaap	Assets Assets	2081664000	USD
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	4771000	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	19659000	USD
CY2020Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	52500000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	0	USD
CY2020Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	54642000	USD
CY2019Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	55161000	USD
CY2020Q4	mgee	Accrued Interest And Taxes AccruedInterestAndTaxes	8539000	USD
CY2019Q4	mgee	Accrued Interest And Taxes AccruedInterestAndTaxes	7244000	USD
CY2020Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	12635000	USD
CY2019Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	12752000	USD
CY2020Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	41664000	USD
CY2019Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	9228000	USD
CY2020Q4	us-gaap	Derivative Liabilities Current DerivativeLiabilitiesCurrent	10160000	USD
CY2019Q4	us-gaap	Derivative Liabilities Current DerivativeLiabilitiesCurrent	10100000	USD
CY2020Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	6015000	USD
CY2019Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	14676000	USD
CY2020Q4	us-gaap	Liabilities Current LiabilitiesCurrent	190926000	USD
CY2019Q4	us-gaap	Liabilities Current LiabilitiesCurrent	128820000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	231471000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	243302000	USD
CY2020Q4	us-gaap	Accumulated Deferred Investment Tax Credit AccumulatedDeferredInvestmentTaxCredit	21821000	USD
CY2019Q4	us-gaap	Accumulated Deferred Investment Tax Credit AccumulatedDeferredInvestmentTaxCredit	763000	USD
CY2020Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	142239000	USD
CY2019Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	164965000	USD
CY2020Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	78168000	USD
CY2019Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	68665000	USD
CY2020Q4	us-gaap	Derivative Liabilities Noncurrent DerivativeLiabilitiesNoncurrent	3980000	USD
CY2019Q4	us-gaap	Derivative Liabilities Noncurrent DerivativeLiabilitiesNoncurrent	15340000	USD
CY2020Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	17532000	USD
CY2019Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	17379000	USD
CY2020Q4	us-gaap	Liabilities Noncurrent LiabilitiesNoncurrent	567422000	USD
CY2019Q4	us-gaap	Liabilities Noncurrent LiabilitiesNoncurrent	573427000	USD
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1
CY2020Q4	us-gaap	Common Stock Value CommonStockValue	36163000	USD
CY2019Q4	us-gaap	Common Stock Value CommonStockValue	34668000	USD
CY2020Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	394408000	USD
CY2019Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	316268000	USD
CY2020Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	545429000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	504740000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	976000000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	855676000	USD
CY2020Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	519303000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	523741000	USD
CY2020Q4	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	1495303000	USD
CY2019Q4	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	1379417000	USD
CY2020Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2253651000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2081664000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	778187000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	84219000	USD
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	45762000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	816644000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	47842000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	855676000	USD
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	51729000	USD
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	79635000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	976000000	USD
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<p style="margin-top: 0; margin-bottom: 0; margin-left: 0.31in; text-indent: -0.13in; text-align: left"><span style="font-family: Calibri; font-weight: bold; font-size: 10.00pt">Use of Estimates - MGE Energy and MGE.</span></p><p style="margin-top: 0; margin-bottom: 0; text-align: left"><span style="font-family: Calibri; font-size: 10.00pt"> </span></p><p style="margin-top: 0; margin-bottom: 0; margin-left: 0.31in; text-align: left"><span style="font-family: Calibri; font-size: 10.00pt">In order to prepare consolidated financial statements in conformity with GAAP, management must make estimates and assumptions. These estimates could affect reported amounts of assets, liabilities, and disclosures at the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from management's estimates. </span></p><p style="margin-top: 0; margin-bottom: 0; margin-left: 0.31in; text-align: left"><span style="font-family: Calibri; font-size: 10.00pt"> </span></p><p style="margin-top: 0; margin-bottom: 0; margin-left: 0.31in; text-align: left"><span style="font-family: Calibri; font-size: 10.00pt">With the global outbreak of the Coronavirus Disease 2019 (COVID-19) and the declaration of a</span></p><p style="margin-top: 0; margin-bottom: 0; margin-left: 0.31in; text-align: left"><span style="font-family: Calibri; font-size: 10.00pt">pandemic by the World Health Organization on March 11, 2020, U.S. governmental authorities have deemed electric and gas utilities to be critical infrastructure. MGE Energy therefore has an obligation to keep operating and maintaining our critical electric and gas infrastructure. Since then, MGE Energy has been subject to, and is following, local, state and federal public health and safety regulations and guidance to control the pandemic. MGE Energy and MGE considered the impact of COVID-19 developments on the assumptions and estimates used in the preparation of these financial statements.</span></p>
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	44738000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	23481000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	644000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	619000	USD
CY2020Q4	us-gaap	Margin Deposit Assets MarginDepositAssets	1657000	USD
CY2019Q4	us-gaap	Margin Deposit Assets MarginDepositAssets	1714000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	47039000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	25814000	USD
CY2020	mgee	Margindepositassetspolicytextblock Margindepositassetspolicytextblock	<p style="margin-top: 0; margin-bottom: 0; margin-left: 0.06in; text-indent: 0.25in; text-align: left"><span style="font-family: Calibri; font-style: italic; font-size: 10.00pt">Receivable – Margin Account</span></p><p style="margin-top: 0; margin-bottom: 0; margin-left: 0.31in; text-align: left"><span style="font-family: Calibri; font-size: 10.00pt">Cash amounts held by counterparties as margin collateral for certain financial transactions are recorded as Receivable – margin account in "Other current assets" on the consolidated balance sheets. The costs being hedged are fuel for electric generation, purchased power, and cost of gas sold.</span></p>
CY2020Q4	mgee	Accounts Receivable Late Payment Charge On Unpaid Receivables AccountsReceivableLatePaymentChargeOnUnpaidReceivables	0.01	pure
CY2020Q4	mgee	Accounts Receivable Late Payment Charge On Unpaid Receivables Suspended AccountsReceivableLatePaymentChargeOnUnpaidReceivablesSuspended	0.01	pure
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	7100000	USD
CY2020	us-gaap	Allowance For Doubtful Accounts Receivable Write Offs AllowanceForDoubtfulAccountsReceivableWriteOffs	1400000	USD
CY2020	us-gaap	Allowance For Doubtful Accounts Receivable Period Increase Decrease AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease	5200000	USD
CY2020Q4	mgee	Public Utilities Inventory Renewable Energy Credit Allowance PublicUtilitiesInventoryRenewableEnergyCreditAllowance	800000	USD
CY2019Q4	mgee	Public Utilities Inventory Renewable Energy Credit Allowance PublicUtilitiesInventoryRenewableEnergyCreditAllowance	600000	USD
CY2020Q4	mgee	Purchase Gas Adjustment Over Under Collected PurchaseGasAdjustmentOverUnderCollected	1800000	USD
CY2019Q4	mgee	Purchase Gas Adjustment Over Under Collected PurchaseGasAdjustmentOverUnderCollected	1900000	USD
CY2020	mgee	Regional Transmission Organization Reduction To Sales And Purchased Power Expense From Net Basis Reporting RegionalTransmissionOrganizationReductionToSalesAndPurchasedPowerExpenseFromNetBasisReporting	61800000	USD
CY2019	mgee	Regional Transmission Organization Reduction To Sales And Purchased Power Expense From Net Basis Reporting RegionalTransmissionOrganizationReductionToSalesAndPurchasedPowerExpenseFromNetBasisReporting	75600000	USD
CY2018	mgee	Regional Transmission Organization Reduction To Sales And Purchased Power Expense From Net Basis Reporting RegionalTransmissionOrganizationReductionToSalesAndPurchasedPowerExpenseFromNetBasisReporting	90300000	USD
CY2020	us-gaap	Public Utilities Allowance For Funds Used During Construction Additions PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions	2100000	USD
CY2019	us-gaap	Public Utilities Allowance For Funds Used During Construction Additions PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions	800000	USD
CY2018	us-gaap	Public Utilities Allowance For Funds Used During Construction Additions PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions	1100000	USD
CY2020	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	5900000	USD
CY2019	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	2300000	USD
CY2018	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	3300000	USD
CY2020Q4	us-gaap	Capitalized Computer Software Net CapitalizedComputerSoftwareNet	20400000	USD
CY2019Q4	us-gaap	Capitalized Computer Software Net CapitalizedComputerSoftwareNet	24600000	USD
CY2020Q4	us-gaap	Capitalized Computer Software Accumulated Amortization CapitalizedComputerSoftwareAccumulatedAmortization	36900000	USD
CY2019Q4	us-gaap	Capitalized Computer Software Accumulated Amortization CapitalizedComputerSoftwareAccumulatedAmortization	31800000	USD
CY2020	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	5100000	USD
CY2018	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	4700000	USD
CY2020Q4	mgee	Capitalized Computer Software Hosting Agreement Net CapitalizedComputerSoftwareHostingAgreementNet	14800000	USD
CY2019Q4	mgee	Capitalized Computer Software Hosting Agreement Net CapitalizedComputerSoftwareHostingAgreementNet	13600000	USD
CY2020Q4	mgee	Capitalized Computer Software Hosting Agreement Accumulated Amortization CapitalizedComputerSoftwareHostingAgreementAccumulatedAmortization	3200000	USD
CY2019Q4	mgee	Capitalized Computer Software Hosting Agreement Accumulated Amortization CapitalizedComputerSoftwareHostingAgreementAccumulatedAmortization	1400000	USD
CY2020	mgee	Capitalized Computer Software Hosting Agreement Amortization CapitalizedComputerSoftwareHostingAgreementAmortization	1800000	USD
CY2019	mgee	Capitalized Computer Software Hosting Agreement Amortization CapitalizedComputerSoftwareHostingAgreementAmortization	1400000	USD
CY2018	mgee	Capitalized Computer Software Hosting Agreement Amortization CapitalizedComputerSoftwareHostingAgreementAmortization	100000	USD
CY2020	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2020	mgee	License Fee Tax Rate Electric Retail Sales LicenseFeeTaxRateElectricRetailSales	0.0319	pure
CY2020	mgee	License Fee Tax Rate Electric Resale By Purchaser LicenseFeeTaxRateElectricResaleByPurchaser	0.0159	pure
CY2020	mgee	License Fee Tax Rate Natural Gas LicenseFeeTaxRateNaturalGas	0.0097	pure
CY2020	us-gaap	Excise And Sales Taxes ExciseAndSalesTaxes	14100000	USD
CY2019	us-gaap	Excise And Sales Taxes ExciseAndSalesTaxes	13900000	USD
CY2018	us-gaap	Excise And Sales Taxes ExciseAndSalesTaxes	14400000	USD
CY2020Q4	mgee	Variable Interest Entity Purchase Power Agreement Plant Capacity Other VariableInterestEntityPurchasePowerAgreementPlantCapacityOther	13	MW
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1769385000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1642683000	USD
CY2020	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	1694000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	1524000	USD
CY2020	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	784000	USD
CY2019	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	792000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	319000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	144000	USD
CY2020	us-gaap	Lease Cost LeaseCost	2797000	USD
CY2019	us-gaap	Lease Cost LeaseCost	2460000	USD
CY2020Q4	mgee	Lease Right Of Use Asset LeaseRightOfUseAsset	21670000	USD
CY2019Q4	mgee	Lease Right Of Use Asset LeaseRightOfUseAsset	16566000	USD
CY2020Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	17532000	USD
CY2019Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	17379000	USD
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	1149000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	945000	USD
CY2020	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	784000	USD
CY2019	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	792000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	319000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	134000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	1480000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	12101000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	5791000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	657000	USD
CY2020Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0432	pure
CY2019Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0437	pure
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0284	pure
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0332	pure
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	1820000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	338000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	1700000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	274000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	1520000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	203000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	959000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	207000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	774000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	211000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	39787000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	8636000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	46560000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	9869000	USD
CY2020Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	27962000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	3858000	USD
CY2020Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	18598000	USD
CY2020Q4	mgee	Operating Lease Liability Current And Noncurrent OperatingLeaseLiabilityCurrentAndNoncurrent	6011000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	3702000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	3629000	USD
CY2020	us-gaap	Investment Tax Credit InvestmentTaxCredit	214000	USD
CY2019	us-gaap	Investment Tax Credit InvestmentTaxCredit	92000	USD
CY2020Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	17906000	USD
CY2019Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	14546000	USD
CY2020Q4	us-gaap	Equity Method Investments EquityMethodInvestments	74462000	USD
CY2019Q4	us-gaap	Equity Method Investments EquityMethodInvestments	71648000	USD
CY2020Q4	us-gaap	Other Investments OtherInvestments	2308000	USD
CY2019Q4	us-gaap	Other Investments OtherInvestments	2298000	USD
CY2020Q4	us-gaap	Investments Investments	94676000	USD
CY2019Q4	us-gaap	Investments Investments	88492000	USD
CY2020	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	622000	USD
CY2019	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	216000	USD
CY2018	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	960000	USD
CY2020	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	379000	USD
CY2019	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	580000	USD
CY2018	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	476000	USD
CY2020Q4	us-gaap	Regulatory Assets RegulatoryAssets	157252000	USD
CY2019Q4	us-gaap	Regulatory Assets RegulatoryAssets	145746000	USD
CY2020Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	183903000	USD
CY2019Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	174193000	USD
CY2019	mgee	Deferredfuelrulesmonitoredcosts Deferredfuelrulesmonitoredcosts	1500000	USD
CY2019	mgee	Deferredfuelrulesmonitoredcosts Deferredfuelrulesmonitoredcosts	1500000	USD
CY2020	mgee	Deferredfuelrulesmonitoredcosts Deferredfuelrulesmonitoredcosts	3200000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	4179000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	8017000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	18622000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	5095000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	4647000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	5163000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	6181000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	3510000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	120000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	4182000	USD
CY2018	us-gaap	Investment Tax Credit InvestmentTaxCredit	100000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	19423000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	19784000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	27434000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.063	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.062	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.063	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	0.002	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	0.001	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	0.001	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	0.062	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	0.057	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	0.003	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Deductions Other EffectiveIncomeTaxRateReconciliationDeductionsOther	0.012	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Deductions Other EffectiveIncomeTaxRateReconciliationDeductionsOther	0.003	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Deductions Other EffectiveIncomeTaxRateReconciliationDeductionsOther	0.006	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	0.020	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	0.024	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	0.018	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Reconciling Items Percent EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent	0.003	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Reconciling Items Percent EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent	0.001	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Other Reconciling Items Percent EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent	-0.001	pure
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.174	pure
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.186	pure
CY2018	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.246	pure
CY2020Q4	us-gaap	Deferred Tax Assets Equity Method Investments DeferredTaxAssetsEquityMethodInvestments	21688000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Equity Method Investments DeferredTaxAssetsEquityMethodInvestments	22576000	USD
CY2020Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	19199000	USD
CY2019Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	0	USD
CY2020Q4	mgee	Deferred Tax Assets Accrued Expenses DeferredTaxAssetsAccruedExpenses	11115000	USD
CY2019Q4	mgee	Deferred Tax Assets Accrued Expenses DeferredTaxAssetsAccruedExpenses	15901000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	35446000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	30968000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Regulatory Assets And Liabilities DeferredTaxAssetsRegulatoryAssetsAndLiabilities	41318000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Regulatory Assets And Liabilities DeferredTaxAssetsRegulatoryAssetsAndLiabilities	35493000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	3852000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	7351000	USD
CY2020Q4	mgee	Deferred Tax Assets Leases DeferredTaxAssetsLeases	6704000	USD
CY2019Q4	mgee	Deferred Tax Assets Leases DeferredTaxAssetsLeases	5167000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	14073000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	12540000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	153395000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	129996000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	38000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	86000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	153357000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	129910000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	257397000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	245083000	USD
CY2020Q4	mgee	Deferred Tax Liabilities Equity Method Investments DeferredTaxLiabilitiesEquityMethodInvestments	51518000	USD
CY2019Q4	mgee	Deferred Tax Liabilities Equity Method Investments DeferredTaxLiabilitiesEquityMethodInvestments	51569000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	595000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	657000	USD
CY2020Q4	mgee	Deferred Tax Liabilities Pension And Other Postretirement Benefits DeferredTaxLiabilitiesPensionAndOtherPostretirementBenefits	45658000	USD
CY2019Q4	mgee	Deferred Tax Liabilities Pension And Other Postretirement Benefits DeferredTaxLiabilitiesPensionAndOtherPostretirementBenefits	45683000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	3852000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	7351000	USD
CY2020Q4	mgee	Deferred Tax Liabilities Deductible Prepayments DeferredTaxLiabilitiesDeductiblePrepayments	9059000	USD
CY2019Q4	mgee	Deferred Tax Liabilities Deductible Prepayments DeferredTaxLiabilitiesDeductiblePrepayments	9078000	USD
CY2020Q4	mgee	Deferred Tax Liabilities Leases DeferredTaxLiabilitiesLeases	6704000	USD
CY2019Q4	mgee	Deferred Tax Liabilities Leases DeferredTaxLiabilitiesLeases	5167000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	10045000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	8624000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	384828000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	373212000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	231471000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	243302000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	2093000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1949000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1924000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	796000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	741000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	425000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	84000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	272000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	608000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	681000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	672000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	2281000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	2093000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1949000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	176000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	191000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	165000	USD
CY2020	mgee	Unrecognized Tax Benefits Decrease Resulting From Interest Expense On Uncertain Tax Positions UnrecognizedTaxBenefitsDecreaseResultingFromInterestExpenseOnUncertainTaxPositions	124000	USD
CY2019	mgee	Unrecognized Tax Benefits Decrease Resulting From Interest Expense On Uncertain Tax Positions UnrecognizedTaxBenefitsDecreaseResultingFromInterestExpenseOnUncertainTaxPositions	137000	USD
CY2018	mgee	Unrecognized Tax Benefits Decrease Resulting From Interest Expense On Uncertain Tax Positions UnrecognizedTaxBenefitsDecreaseResultingFromInterestExpenseOnUncertainTaxPositions	136000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	102000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	122000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	162000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	154000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	176000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	191000	USD
CY2019Q4	mgee	Unrecognized Tax Benefits Current Period Tax Positions Permanent Differences UnrecognizedTaxBenefitsCurrentPeriodTaxPositionsPermanentDifferences	100000	USD
CY2018Q4	mgee	Unrecognized Tax Benefits Current Period Tax Positions Permanent Differences UnrecognizedTaxBenefitsCurrentPeriodTaxPositionsPermanentDifferences	300000	USD
CY2020Q4	mgee	Unrecognized Tax Benefits Current Period Tax Positions Permanent Differences UnrecognizedTaxBenefitsCurrentPeriodTaxPositionsPermanentDifferences	0	USD
CY2020	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	4700000	USD
CY2019	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	4400000	USD
CY2018	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	3900000	USD
CY2019	mgee	Defined Benefit Plan Deferred Net Periodic Benefit Costs DefinedBenefitPlanDeferredNetPeriodicBenefitCosts	6200000	USD
CY2020	mgee	Defined Benefit Plan Deferred Net Periodic Benefit Costs DefinedBenefitPlanDeferredNetPeriodicBenefitCosts	-900000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	481273000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	434922000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1300000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3000000.0	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1100000	USD
CY2020Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	685000	USD
CY2019Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	0	USD
CY2020Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0.0015	pure
CY2019Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0	pure
CY2020	us-gaap	Shortterm Debt Maximum Amount Outstanding During Period ShorttermDebtMaximumAmountOutstandingDuringPeriod	52500000	USD
CY2019	us-gaap	Shortterm Debt Maximum Amount Outstanding During Period ShorttermDebtMaximumAmountOutstandingDuringPeriod	56000000	USD
CY2020	us-gaap	Shortterm Debt Average Outstanding Amount ShorttermDebtAverageOutstandingAmount	6393000	USD
CY2019	us-gaap	Shortterm Debt Average Outstanding Amount ShorttermDebtAverageOutstandingAmount	18364000	USD
CY2020	mgee	Short Term Debt Weighted Average Interest Rate During Period ShortTermDebtWeightedAverageInterestRateDuringPeriod	0.0043	pure
CY2019	mgee	Short Term Debt Weighted Average Interest Rate During Period ShortTermDebtWeightedAverageInterestRateDuringPeriod	0.0216	pure
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	4771000	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	19659000	USD
CY2020Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	4146000	USD
CY2019Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	4479000	USD
CY2020Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	519303000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	523741000	USD
CY2020Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	52500000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	4771000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	4889000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	54314000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	5146000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	5285000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	453815000	USD
CY2020	mgee	Stock Issued During Period Under The Stock Plan StockIssuedDuringPeriodUnderTheStockPlan	0	shares
CY2020	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	1500000	shares
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	51700000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	47800000	USD
CY2020	us-gaap	Dilutive Securities DilutiveSecurities	0	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Next Twelve Months PurchaseObligationDueInNextTwelveMonths	79290000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Second Year PurchaseObligationDueInSecondYear	47674000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Third Year PurchaseObligationDueInThirdYear	32880000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Fourth Year PurchaseObligationDueInFourthYear	29546000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Fifth Year PurchaseObligationDueInFifthYear	29000000	USD
CY2020Q4	us-gaap	Purchase Obligation Due After Fifth Year PurchaseObligationDueAfterFifthYear	61864000	USD
CY2020Q4	us-gaap	Other Commitment Due In Next Twelve Months OtherCommitmentDueInNextTwelveMonths	333000	USD
CY2020Q4	us-gaap	Other Commitment Due In Second Year OtherCommitmentDueInSecondYear	333000	USD
CY2020Q4	us-gaap	Other Commitment Due In Third Year OtherCommitmentDueInThirdYear	333000	USD
CY2020Q4	us-gaap	Other Commitment Due After Fifth Year OtherCommitmentDueAfterFifthYear	2999000	USD
CY2020Q4	us-gaap	Other Commitment Due In Fourth Year OtherCommitmentDueInFourthYear	333000	USD
CY2020Q4	us-gaap	Other Commitment Due In Fifth Year OtherCommitmentDueInFifthYear	333000	USD
CY2019Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	28355000	USD
CY2018Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	29980000	USD
CY2020	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	3503000	USD
CY2019	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	1586000	USD
CY2020	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	1366000	USD
CY2019	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	1574000	USD
CY2020	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	372000	USD
CY2019	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	323000	USD
CY2020	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	-1656000	USD
CY2019	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	-4462000	USD
CY2020Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	31196000	USD
CY2019Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	28355000	USD
CY2020	us-gaap	Derivatives Methods Of Accounting Hedging Derivatives DerivativesMethodsOfAccountingHedgingDerivatives	<span style="font-family: Calibri; font-size: 10.00pt">As part of its regular operations, MGE enters into contracts, including options, swaps, futures, forwards, and other contractual commitments, to manage its exposure to commodity prices. To the extent that these contracts are derivatives, MGE assesses whether or not the normal purchases or normal sales exclusion applies. For contracts to which this exclusion cannot be applied, the derivatives are recognized in the consolidated balance sheets at fair value. MGE's financial commodity derivative activities are conducted in accordance with its electric and gas risk management program, which is approved by the PSCW and limits the volume MGE can hedge with specific risk management strategies. The maximum length of time over which cash flows related to energy commodities can be hedged is </span><span style="font-family: Calibri; font-size: 10.00pt"><span style="-sec-ix-hidden: ID_2041">four</span> years. If the derivative qualifies for regulatory deferral, the derivatives are marked to fair value and are offset with a corresponding regulatory asset or liability depending on whether the derivative is in a net loss or net gain position, respectively. The deferred gain or loss is recognized in earnings in the delivery month applicable to the instrument. Gains and losses related to hedges qualifying for regulatory treatment are recoverable in gas rates through the PGA or in electric rates as a component of the fuel rules mechanism.</span>
CY2020Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	0	USD
CY2020Q4	mgee	Counterparties In Default CounterpartiesInDefault	0
CY2020Q4	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	0	USD
CY2019Q4	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	1500000	USD
CY2019	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Sales FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSales	0	USD
CY2019	mgee	Fair Value Inputs Delivery Points Basis Adjustment Off Peak FairValueInputsDeliveryPointsBasisAdjustmentOffPeak	0.927	pure
CY2019Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-26456000	USD
CY2018Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-32002000	USD
CY2017Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-42026000	USD
CY2020	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets	12402000	USD
CY2019	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets	5545000	USD
CY2018	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets	10024000	USD
CY2020	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Other Comprehensive Income Loss FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInOtherComprehensiveIncomeLoss	0	USD
CY2019	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Other Comprehensive Income Loss FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInOtherComprehensiveIncomeLoss	0	USD
CY2018	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Other Comprehensive Income Loss FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInOtherComprehensiveIncomeLoss	0	USD
CY2020	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Earnings FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings	-6439000	USD
CY2019	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Earnings FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings	-3765000	USD
CY2018	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Earnings FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings	132000	USD
CY2020	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets	-87000	USD
CY2019	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets	-70000	USD
CY2018	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets	-47000	USD
CY2020	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Purchases FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases	22232000	USD
CY2019	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Purchases FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases	22974000	USD
CY2018	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Purchases FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases	23643000	USD
CY2020	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Sales FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSales	0	USD
CY2020	mgee	Fair Value Inputs Delivery Points Basis Adjustment On Peak FairValueInputsDeliveryPointsBasisAdjustmentOnPeak	0.942	pure
CY2019	mgee	Fair Value Inputs Delivery Points Basis Adjustment On Peak FairValueInputsDeliveryPointsBasisAdjustmentOnPeak	0.921	pure
CY2020	mgee	Fair Value Inputs Delivery Points Basis Adjustment Off Peak FairValueInputsDeliveryPointsBasisAdjustmentOffPeak	0.945	pure
CY2018	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Sales FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSales	0	USD
CY2020	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Issues FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues	0	USD
CY2019	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Issues FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues	0	USD
CY2018	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Issues FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues	0	USD
CY2020	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Settlements FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements	15707000	USD
CY2019	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Settlements FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements	19138000	USD
CY2018	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Settlements FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements	23728000	USD
CY2020	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Transfers Net FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersNet	0	USD
CY2019	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Transfers Net FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersNet	0	USD
CY2018	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Transfers Net FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersNet	0	USD
CY2020Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-14055000	USD
CY2019Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-26456000	USD
CY2018Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-32002000	USD
CY2020	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Change In Unrealized Gain Loss FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	0	USD
CY2019	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Change In Unrealized Gain Loss FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	0	USD
CY2018	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Change In Unrealized Gain Loss FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	0	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	212197000	USD
CY2020Q1	us-gaap	Regulated Operating Revenue Electric Non Nuclear RegulatedOperatingRevenueElectricNonNuclear	93028000	USD
CY2020Q2	us-gaap	Regulated Operating Revenue Electric Non Nuclear RegulatedOperatingRevenueElectricNonNuclear	93961000	USD
CY2020	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Earnings FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings	-6439000	USD
CY2019	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Earnings FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings	-3765000	USD
CY2018	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Earnings FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings	132000	USD
CY2018	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	559768000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	84219000	USD
CY2020Q4	us-gaap	Assets Assets	2253651000	USD
CY2019Q4	us-gaap	Assets Assets	2081664000	USD
CY2018Q4	us-gaap	Assets Assets	1988618000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	203139000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	164036000	USD
CY2020Q3	us-gaap	Regulated Operating Revenue Electric Non Nuclear RegulatedOperatingRevenueElectricNonNuclear	116568000	USD
CY2020Q4	us-gaap	Regulated Operating Revenue Electric Non Nuclear RegulatedOperatingRevenueElectricNonNuclear	90815000	USD
CY2020Q1	us-gaap	Regulated Operating Revenue Gas RegulatedOperatingRevenueGas	56845000	USD
CY2020Q2	us-gaap	Regulated Operating Revenue Gas RegulatedOperatingRevenueGas	23079000	USD
CY2020Q3	us-gaap	Regulated Operating Revenue Gas RegulatedOperatingRevenueGas	18643000	USD
CY2020Q4	us-gaap	Regulated Operating Revenue Gas RegulatedOperatingRevenueGas	45694000	USD
CY2020Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.353
CY2020Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.370
CY2020Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.370
CY2019Q1	us-gaap	Regulated Operating Revenue Electric Non Nuclear RegulatedOperatingRevenueElectricNonNuclear	97469000	USD
CY2020Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	18712000	USD
CY2020Q1	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-390000	USD
CY2020Q2	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	1011000	USD
CY2020Q3	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	769000	USD
CY2020Q4	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	454000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3740000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7300000	USD
CY2020Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3370000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	26037000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	18791000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	31794000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	15796000	USD
CY2020Q1	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.75
CY2020Q2	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.53
CY2020Q3	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.88
CY2020Q4	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.44
CY2020Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.353
CY2020Q1	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	149873000	USD
CY2020Q2	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	117040000	USD
CY2020Q3	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	135211000	USD
CY2020Q1	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	118433000	USD
CY2020Q2	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	95520000	USD
CY2020Q3	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	96886000	USD
CY2020Q4	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	117797000	USD
CY2020Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	31440000	USD
CY2020Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	21520000	USD
CY2020Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	38325000	USD
CY2019Q2	us-gaap	Regulated Operating Revenue Electric Non Nuclear RegulatedOperatingRevenueElectricNonNuclear	97077000	USD
CY2019Q3	us-gaap	Regulated Operating Revenue Electric Non Nuclear RegulatedOperatingRevenueElectricNonNuclear	120821000	USD
CY2019Q4	us-gaap	Regulated Operating Revenue Electric Non Nuclear RegulatedOperatingRevenueElectricNonNuclear	93613000	USD
CY2019Q1	us-gaap	Regulated Operating Revenue Gas RegulatedOperatingRevenueGas	70100000	USD
CY2019Q2	us-gaap	Regulated Operating Revenue Gas RegulatedOperatingRevenueGas	25070000	USD
CY2019Q3	us-gaap	Regulated Operating Revenue Gas RegulatedOperatingRevenueGas	17377000	USD
CY2019Q4	us-gaap	Regulated Operating Revenue Gas RegulatedOperatingRevenueGas	47328000	USD
CY2019Q1	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	167569000	USD
CY2019Q2	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	122147000	USD
CY2019Q3	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	138198000	USD
CY2019Q4	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	140941000	USD
CY2019Q1	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	137057000	USD
CY2019Q2	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	102364000	USD
CY2019Q3	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	99460000	USD
CY2019Q4	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	119064000	USD
CY2019Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	30512000	USD
CY2019Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	19783000	USD
CY2019Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	38738000	USD
CY2019Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	21877000	USD
CY2019Q1	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-796000	USD
CY2019Q2	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-730000	USD
CY2019Q3	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-627000	USD
CY2019Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3116000	USD
CY2019Q4	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-2099000	USD
CY2019Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	5709000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3505000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7454000	USD
CY2019	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	1614943	USD
CY2019	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	20160	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	15548000	USD
CY2019	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1530496	USD
CY2019Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	3258269	USD
CY2019Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	3258269	USD
CY2020	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	5164943	USD
CY2020	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	26400	USD
CY2020	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1373047	USD
CY2020Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	7076565	USD
CY2018Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	3153662	USD
CY2018Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	3153662	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	30657000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	16662000	USD
CY2019Q1	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.69
CY2019Q2	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.45
CY2019Q3	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.88
CY2019Q4	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.48
CY2019Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.338
CY2019Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.338
CY2019Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.353
CY2019Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.353
CY2017Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	3174945	USD
CY2018	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	1065970	USD
CY2018	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	320400	USD
CY2018	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1407653	USD

Files In Submission

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$MGEE
MGE ENERGY INC Stock $mgee

2020 Q4 Form 10-K Financial Statement

#000116172821000013 Filed on February 24, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$MGEE MGE ENERGY INC Stock $mgee

2020 Q4 Form 10-K Financial Statement

#000116172821000013 Filed on February 24, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$MGEE
MGE ENERGY INC Stock $mgee