$MGEE
MGE ENERGY INC Stock $mgee

$mgee Overview Financials Valuation SEC Filings Company Website

2018 Q1 Form 10-K Financial Statement

#000116172818000003 Filed on February 23, 2018

Income Statement

Concept	2018 Q1	2017 Q4	2016 Q4
Revenue	$157.6M	$140.3M	$138.9M
YoY Change	0.52%	0.97%	6.07%
Cost Of Revenue	$56.70M	$37.20M	$41.10M
YoY Change	10.96%	-9.49%	11.38%
Gross Profit	$100.9M	$103.1M	$97.80M
YoY Change	-4.54%	5.42%	3.93%
Gross Profit Margin	64.01%	73.5%	70.4%
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$13.60M	$13.50M	$11.20M
YoY Change	4.62%	20.54%	0.0%
% of Gross Profit	13.48%	13.09%	11.45%
Operating Expenses	$74.70M	$77.90M	$73.90M
YoY Change	1.08%	5.41%	2.78%
Operating Profit	$26.19M	$25.20M	$23.96M
YoY Change	-17.74%	5.17%	8.03%
Interest Expense	-$4.700M	-$4.800M	-$4.900M
YoY Change	-4.08%	-2.04%	-2.0%
% of Operating Profit	-17.95%	-19.05%	-20.45%
Other Income/Expense, Net	$4.919M	$2.400M	$3.000M
YoY Change	39.55%	-20.0%	100.0%
Pretax Income	$26.37M	$22.70M	$22.10M
YoY Change	-13.45%	2.71%	18.82%
Income Tax	$6.367M	-$13.39M	$7.570M
% Of Pretax Income	24.15%	-59.0%	34.25%
Net Earnings	$20.00M	$36.13M	$14.50M
YoY Change	3.63%	149.17%	29.11%
Net Earnings / Revenue	12.69%	25.76%	10.44%
Basic Earnings Per Share
Diluted Earnings Per Share	$576.4K	$1.040M	$417.9K
COMMON SHARES
Basic Shares Outstanding	34.67M shares	34.67M shares	34.67M shares
Diluted Shares Outstanding

Balance Sheet

Concept	2018 Q1	2017 Q4	2016 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments	$101.2M	$108.0M	$96.00M
YoY Change	-14.02%	12.5%	17.94%
Cash & Equivalents	$101.2M	$108.0M	$95.96M
Short-Term Investments
Other Short-Term Assets	$11.18M	$12.51M	$12.29M
YoY Change	-80.6%	1.74%	16.3%
Inventory	$36.70M	$43.80M	$41.10M
Prepaid Expenses
Receivables	$43.31M	$42.30M	$39.89M
Other Receivables	$5.851M	$9.440M	$8.530M
Total Short-Term Assets	$248.7M	$290.6M	$275.5M
YoY Change	-2.11%	5.49%	8.15%
LONG-TERM ASSETS
Property, Plant & Equipment	$1.366B	$1.341B	$1.282B
YoY Change	6.14%	4.63%	3.11%
Goodwill
YoY Change
Intangibles
YoY Change
Long-Term Investments	$72.20M	$20.40M	$73.62M
YoY Change	-11.74%	-72.29%	4.2%
Other Assets	$2.150M	$731.0K	$1.088M
YoY Change	-98.67%	-32.81%	-18.32%
Total Long-Term Assets	$1.595B	$1.565B	$1.526B
YoY Change	4.16%	2.56%	3.66%
TOTAL ASSETS
Total Short-Term Assets	$248.7M	$290.6M	$275.5M
Total Long-Term Assets	$1.595B	$1.565B	$1.526B
Total Assets	$1.844B	$1.855B	$1.801B
YoY Change	3.26%	3.01%	4.32%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$35.03M	$47.65M	$47.80M
YoY Change	-5.08%	-0.32%	17.07%
Accrued Expenses	$12.90M	$17.80M	$17.40M
YoY Change	-19.88%	2.3%	6.75%
Deferred Revenue
YoY Change
Short-Term Debt	$3.000M	$4.000M	$0.00
YoY Change
Long-Term Debt Due	$24.48M	$24.45M	$4.333M
YoY Change	456.3%	464.32%	1.57%
Total Short-Term Liabilities	$106.2M	$126.5M	$103.5M
YoY Change	27.22%	22.23%	23.01%
LONG-TERM LIABILITIES
Long-Term Debt	$397.1M	$398.2M	$382.8M
YoY Change	1.44%	4.02%	-1.02%
Other Long-Term Liabilities	$68.75M	$69.04M	$66.43M
YoY Change	-65.14%	3.94%	7.45%
Total Long-Term Liabilities	$553.2M	$552.3M	$590.7M
YoY Change	-6.03%	-6.49%	4.53%
TOTAL LIABILITIES
Total Short-Term Liabilities	$106.2M	$126.5M	$103.5M
Total Long-Term Liabilities	$553.2M	$552.3M	$590.7M
Total Liabilities	$659.4M	$678.8M	$694.2M
YoY Change	-37.35%	-2.21%	6.93%
SHAREHOLDERS EQUITY
Retained Earnings		$426.9M	$373.0M
YoY Change		14.46%	9.96%
Common Stock		$34.67M	$34.67M
YoY Change		0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$787.0M	$778.2M	$724.1M
YoY Change
Total Liabilities & Shareholders Equity	$1.844B	$1.855B	$1.801B
YoY Change	3.26%	3.01%	4.32%

Cashflow Statement

Concept	2018 Q1	2017 Q4	2016 Q4
OPERATING ACTIVITIES
Net Income	$20.00M	$36.13M	$14.50M
YoY Change	3.63%	149.17%	29.11%
Depreciation, Depletion And Amortization	$13.60M	$13.50M	$11.20M
YoY Change	4.62%	20.54%	0.0%
Cash From Operating Activities	$46.98M	$35.30M	$18.30M
YoY Change	13.88%	92.9%	-1.08%
INVESTING ACTIVITIES
Capital Expenditures	$37.63M	-$41.80M	-$21.40M
YoY Change	133.49%	95.33%	8.63%
Acquisitions
YoY Change
Other Investing Activities	$35.00K	-$3.800M	-$900.0K
YoY Change	-103.77%	322.22%	125.0%
Cash From Investing Activities	-$39.54M	-$45.70M	-$22.20M
YoY Change	118.13%	105.86%	10.45%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net	$1.103M
YoY Change	-96.45%
Cash From Financing Activities	-$13.28M	14.50M	-11.70M
YoY Change	554.71%	-223.93%	4.46%
NET CHANGE
Cash From Operating Activities	$46.98M	35.30M	18.30M
Cash From Investing Activities	-$39.54M	-45.70M	-22.20M
Cash From Financing Activities	-$13.28M	14.50M	-11.70M
Net Change In Cash	-$5.849M	4.100M	-15.60M
YoY Change	-127.73%	-126.28%	21.87%
FREE CASH FLOW
Cash From Operating Activities	$46.98M	$35.30M	$18.30M
Capital Expenditures	$37.63M	-$41.80M	-$21.40M
Free Cash Flow	$9.347M	$77.10M	$39.70M
YoY Change	-62.81%	94.21%	3.93%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2015Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	3694080	USD
CY2017	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-748000	USD
CY2017	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	10125000	USD
CY2015	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-52243000	USD
CY2015	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	595500	USD
CY2017Q4	mgee	Accrued Interest And Taxes AccruedInterestAndTaxes	5602000	USD
CY2016Q4	mgee	Accrued Interest And Taxes AccruedInterestAndTaxes	5495000	USD
CY2016	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	41775000	USD
CY2017	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	43682000	USD
CY2017	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	11993000	USD
CY2016Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	95959000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	107952000	USD
CY2017	us-gaap	Interest Paid Net InterestPaidNet	19176000	USD
CY2017	us-gaap	Increase Decrease In Prepaid Taxes IncreaseDecreaseInPrepaidTaxes	-101000	USD
CY2017	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	8803000	USD
CY2017	us-gaap	Income Taxes Paid IncomeTaxesPaid	27149000	USD
CY2017	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	2568000	USD
CY2017	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	831000	USD
CY2017	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	0	USD
CY2017	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	11304000	USD
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	132991000	USD
CY2017	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	11081000	USD
CY2017	us-gaap	Increase Decrease In Accounts And Other Receivables IncreaseDecreaseInAccountsAndOtherReceivables	4502000	USD
CY2017	us-gaap	Increase Decrease In Unbilled Receivables IncreaseDecreaseInUnbilledReceivables	1554000	USD
CY2017	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	34358000	USD
CY2017	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	4000000	USD
CY2017	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-597000	USD
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-4637000	USD
CY2017	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	1016000	USD
CY2017	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-5290000	USD
CY2017	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-32000	USD
CY2015	us-gaap	Increase Decrease In Prepaid Taxes IncreaseDecreaseInPrepaidTaxes	-3658000	USD
CY2015	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	40043000	USD
CY2015	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	10130000	USD
CY2015	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	141185000	USD
CY2015	us-gaap	Increase Decrease In Unbilled Receivables IncreaseDecreaseInUnbilledReceivables	-6254000	USD
CY2015	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	2646000	USD
CY2015	us-gaap	Increase Decrease In Accounts And Other Receivables IncreaseDecreaseInAccountsAndOtherReceivables	-4508000	USD
CY2017	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	1275000	USD
CY2015	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	-597000	USD
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CY2015	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	7728000	USD
CY2015	us-gaap	Interest Paid Net InterestPaidNet	19636000	USD
CY2017	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	16602000	USD
CY2015	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	21927000	USD
CY2015	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	72030000	USD
CY2015	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	13676000	USD
CY2015	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	4182000	USD
CY2015	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	596000	USD
CY2015	us-gaap	Income Taxes Paid IncomeTaxesPaid	23800000	USD
CY2015	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-721000	USD
CY2015Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	81384000	USD
CY2015	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-3499000	USD
CY2015	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-7000000	USD
CY2015	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	1053000	USD
CY2015	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	6645000	USD
CY2015	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	3333000	USD
CY2016Q4	us-gaap	Energy Related Inventory Other Fossil Fuel EnergyRelatedInventoryOtherFossilFuel	9757000	USD
CY2016Q4	us-gaap	Energy Related Inventory Gas Stored Underground EnergyRelatedInventoryGasStoredUnderground	12819000	USD
CY2016Q4	us-gaap	Prepaid Taxes PrepaidTaxes	26636000	USD
CY2016Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	6414000	USD
CY2016Q4	us-gaap	Other Assets Current OtherAssetsCurrent	12293000	USD
CY2016Q4	us-gaap	Assets Current AssetsCurrent	275515000	USD
CY2016Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	158485000	USD
CY2016Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	1088000	USD
CY2016Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	36790000	USD
CY2016Q4	us-gaap	Investments Investments	76290000	USD
CY2016Q4	us-gaap	Assets Assets	1801060000	USD
CY2016Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	4333000	USD
CY2016Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	47799000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-4082000	USD
CY2015	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	-978000	USD
CY2017	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	3948000	USD
CY2017Q4	us-gaap	Other Inventory Supplies OtherInventorySupplies	22614000	USD
CY2017Q4	us-gaap	Energy Related Inventory Other Fossil Fuel EnergyRelatedInventoryOtherFossilFuel	8256000	USD
CY2017Q4	us-gaap	Energy Related Inventory Gas Stored Underground EnergyRelatedInventoryGasStoredUnderground	12923000	USD
CY2017Q4	us-gaap	Prepaid Taxes PrepaidTaxes	26535000	USD
CY2017Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	7888000	USD
CY2017Q4	us-gaap	Other Assets Current OtherAssetsCurrent	12507000	USD
CY2017Q4	us-gaap	Assets Current AssetsCurrent	290631000	USD
CY2017Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	142567000	USD
CY2017Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	731000	USD
CY2017Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	58044000	USD
CY2017Q4	us-gaap	Investments Investments	67772000	USD
CY2017Q4	us-gaap	Assets Assets	1855182000	USD
CY2017Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	24452000	USD
CY2017Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	47645000	USD
CY2015	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	3963000	USD
CY2015	us-gaap	Increase Decrease In Other Noncurrent Assets And Liabilities Net IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	-5143000	USD
CY2016Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.295
CY2016Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	11892000	USD
CY2016Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	19456000	USD
CY2016Q4	us-gaap	Liabilities Current LiabilitiesCurrent	103505000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	383813000	USD
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CY2016Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	74347000	USD
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CY2016Q4	us-gaap	Liabilities Noncurrent LiabilitiesNoncurrent	590676000	USD
CY2016Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	316268000	USD
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CY2016Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	202000	USD
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CY2016Q4	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	426000	USD
CY2016Q4	us-gaap	Common Stock Value CommonStockValue	34668000	USD
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CY2017Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	225130000	USD
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CY2017Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	154153000	USD
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CY2016Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	34668000	shares
CY2016Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	6910000	USD
CY2015	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	40043000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-101000	USD
CY2017	dei	Entity Registrant Name EntityRegistrantName	MGE Energy Inc
CY2017	dei	Document Period End Date DocumentPeriodEndDate	2017-12-31
CY2017	dei	Amendment Flag AmendmentFlag	false
CY2017	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2017
CY2017	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2017Q2	dei	Entity Public Float EntityPublicFloat	2225394029	USD
CY2018Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	34668370	shares
CY2017	us-gaap	Use Of Estimates UseOfEstimates	<div><p style='text-align:left;margin-top:0pt;margin-bottom:0pt;line-height:12pt;' ><font style='font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:27pt;' >Use of Estimates - MGE Energy and MGE.</font></p><p style='text-align:left;line-height:12pt;' ></p><p style='text-align:left;margin-top:0pt;margin-bottom:0pt;line-height:12pt;' ><font style='font-family:Times New Roman;font-size:10pt;margin-left:45pt;' >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.</font></p></div>
CY2017Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	5633000	USD
CY2016	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-155000	USD
CY2016Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	34668000	shares
CY2017Q4	mgee	Accounts Receivable Late Payment Charge On Unpaid Receivables AccountsReceivableLatePaymentChargeOnUnpaidReceivables	0.01	pure
CY2016Q4	mgee	Public Utilities Inventory Renewable Energy Credit Allowance PublicUtilitiesInventoryRenewableEnergyCreditAllowance	300000	USD
CY2017Q4	mgee	Public Utilities Inventory Renewable Energy Credit Allowance PublicUtilitiesInventoryRenewableEnergyCreditAllowance	500000	USD
CY2017Q4	mgee	Purchase Gas Adjustment Over Under Collected PurchaseGasAdjustmentOverUnderCollected	1400000	USD
CY2016Q4	mgee	Purchase Gas Adjustment Over Under Collected PurchaseGasAdjustmentOverUnderCollected	900000	USD
CY2017Q4	us-gaap	Capitalized Computer Software Net CapitalizedComputerSoftwareNet	11100000	USD
CY2016Q4	us-gaap	Capitalized Computer Software Net CapitalizedComputerSoftwareNet	12300000	USD
CY2016	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	3000000	USD
CY2017	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	3300000	USD
CY2017	mgee	License Fee Tax Rate Electric Retail Sales LicenseFeeTaxRateElectricRetailSales	0.0319	pure
CY2017	mgee	License Fee Tax Rate Electric Resale By Purchaser LicenseFeeTaxRateElectricResaleByPurchaser	0.0159	pure
CY2017	mgee	License Fee Tax Rate Natural Gas LicenseFeeTaxRateNaturalGas	0.0097	pure
CY2017	us-gaap	Excise And Sales Taxes ExciseAndSalesTaxes	14100000	USD
CY2016	us-gaap	Excise And Sales Taxes ExciseAndSalesTaxes	14500000	USD
CY2015	us-gaap	Excise And Sales Taxes ExciseAndSalesTaxes	14700000	USD
CY2017	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2016	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2015	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2017Q4	mgee	Variable Interest Entity Purchase Power Agreement Plant Capacity Other VariableInterestEntityPurchasePowerAgreementPlantCapacityOther	61	MW
CY2016Q4	mgee	Variable Interest Entity Purchase Power Agreement Plant Capacity Other VariableInterestEntityPurchasePowerAgreementPlantCapacityOther	51	MW
CY2017Q4	us-gaap	Available For Sale Securities Amortized Cost AvailableForSaleSecuritiesAmortizedCost	6662000	USD
CY2016Q4	us-gaap	Available For Sale Securities Amortized Cost AvailableForSaleSecuritiesAmortizedCost	2216000	USD
CY2017Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	7291000	USD
CY2016Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	2554000	USD
CY2017Q4	us-gaap	Equity Method Investments EquityMethodInvestments	60426000	USD
CY2016Q4	us-gaap	Equity Method Investments EquityMethodInvestments	73616000	USD
CY2017Q4	us-gaap	Other Investments OtherInvestments	55000	USD
CY2016Q4	us-gaap	Other Investments OtherInvestments	120000	USD
CY2016Q4	mgee	Availableforsalesecuritiesgrossunrealizedgainaccumulatedininvestments Availableforsalesecuritiesgrossunrealizedgainaccumulatedininvestments	346000	USD
CY2017Q4	mgee	Availableforsalesecuritiesgrossunrealizedgainaccumulatedininvestments Availableforsalesecuritiesgrossunrealizedgainaccumulatedininvestments	675000	USD
CY2017	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	677000	USD
CY2017	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	522000	USD
CY2016	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	121000	USD
CY2016	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	408000	USD
CY2015	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	19000	USD
CY2015	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	10000	USD
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	19659000	USD
CY2017Q4	us-gaap	Regulatory Assets RegulatoryAssets	150455000	USD
CY2016Q4	us-gaap	Regulatory Assets RegulatoryAssets	164899000	USD
CY2016Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	29083000	USD
CY2017Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	159786000	USD
CY2017Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	4270000	USD
CY2016Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	4118000	USD
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	4771000	USD
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	4889000	USD
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	368559000	USD
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	24452000	USD
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	4553000	USD
CY2017	mgee	Short Term Debt Weighted Average Interest Rate During Period ShortTermDebtWeightedAverageInterestRateDuringPeriod	0.0118	pure
CY2016	mgee	Short Term Debt Weighted Average Interest Rate During Period ShortTermDebtWeightedAverageInterestRateDuringPeriod	0	pure
CY2017	us-gaap	Shortterm Debt Maximum Amount Outstanding During Period ShorttermDebtMaximumAmountOutstandingDuringPeriod	7500000	USD
CY2017	us-gaap	Shortterm Debt Average Outstanding Amount ShorttermDebtAverageOutstandingAmount	304000	USD
CY2016	us-gaap	Shortterm Debt Average Outstanding Amount ShorttermDebtAverageOutstandingAmount	0	USD
CY2016	us-gaap	Shortterm Debt Maximum Amount Outstanding During Period ShorttermDebtMaximumAmountOutstandingDuringPeriod	0	USD
CY2017	mgee	Fair Value Inputs Delivery Points Basis Adjustment On Peak FairValueInputsDeliveryPointsBasisAdjustmentOnPeak	0.923	pure
CY2017	mgee	Fair Value Inputs Delivery Points Basis Adjustment Off Peak FairValueInputsDeliveryPointsBasisAdjustmentOffPeak	0.941	pure
CY2017	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
CY2016	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
CY2015	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
CY2017	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Earnings FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings	-3718000	USD
CY2016	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Earnings FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings	-5347000	USD
CY2017	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets	-9000	USD
CY2016	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets	-142000	USD
CY2015	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedincurrentassets	0	USD
CY2017	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Purchases FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases	24181000	USD
CY2016	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Purchases FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases	23346000	USD
CY2015	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Purchases FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases	23052000	USD
CY2017	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Sales FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSales	0	USD
CY2016	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Sales FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSales	0	USD
CY2015	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Sales FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSales	0	USD
CY2017	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Issues FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues	0	USD
CY2016	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Issues FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues	0	USD
CY2015	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Issues FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues	0	USD
CY2017	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Settlements FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements	20455000	USD
CY2016	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Settlements FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements	17857000	USD
CY2015	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Settlements FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements	16416000	USD
CY2017	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Transfers Net FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersNet	0	USD
CY2016	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Transfers Net FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersNet	0	USD
CY2015	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35	pure
CY2015	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.052	pure
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	0.016	pure
CY2015	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Transfers Net FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersNet	0	USD
CY2017Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-42026000	USD
CY2016Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-50306000	USD
CY2017	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	21125000	USD
CY2017	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	5129000	USD
CY2017	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-8346000	USD
CY2017	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	4264000	USD
CY2017	us-gaap	Investment Tax Credit InvestmentTaxCredit	-78000	USD
CY2016	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	17571000	USD
CY2016	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	4850000	USD
CY2016	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	3287000	USD
CY2016	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	16908000	USD
CY2016	us-gaap	Investment Tax Credit InvestmentTaxCredit	-103000	USD
CY2015	us-gaap	Investment Tax Credit InvestmentTaxCredit	-175000	USD
CY2015	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	15951000	USD
CY2015	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	2774000	USD
CY2015	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	16837000	USD
CY2015	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	5976000	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35	pure
CY2017	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.051	pure
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	0	pure
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Deductions Qualified Production Activities EffectiveIncomeTaxRateReconciliationDeductionsQualifiedProductionActivities	0.014	pure
CY2017	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.185	pure
CY2016	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35	pure
CY2016	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.051	pure
CY2015	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.367	pure
CY2016	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.36	pure
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Deductions Qualified Production Activities EffectiveIncomeTaxRateReconciliationDeductionsQualifiedProductionActivities	0.014	pure
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	0.002	pure
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	0.001	pure
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Deductions Qualified Production Activities EffectiveIncomeTaxRateReconciliationDeductionsQualifiedProductionActivities	0.013	pure
CY2016Q4	mgee	Deferred Tax Liabilities Deductible Prepayments DeferredTaxLiabilitiesDeductiblePrepayments	8404000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	69000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	19340000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	143029000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Regulatory Assets And Liabilities DeferredTaxAssetsRegulatoryAssetsAndLiabilities	903000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	16606000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	32196000	USD
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	0.016	pure
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	0.018	pure
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Deductions Other EffectiveIncomeTaxRateReconciliationDeductionsOther	0.001	pure
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Deductions Other EffectiveIncomeTaxRateReconciliationDeductionsOther	0.002	pure
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Deductions Other EffectiveIncomeTaxRateReconciliationDeductionsOther	0.002	pure
CY2017Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	238437000	USD
CY2017Q4	mgee	Deferred Tax Liabilities Equity Method Investments DeferredTaxLiabilitiesEquityMethodInvestments	48324000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	832000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	11525000	USD
CY2017Q4	mgee	Deferred Tax Liabilities Deductible Prepayments DeferredTaxLiabilitiesDeductiblePrepayments	6169000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	9389000	USD
CY2017Q4	mgee	Deferred Tax Assets Accrued Expenses DeferredTaxAssetsAccruedExpenses	15135000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Regulatory Assets And Liabilities DeferredTaxAssetsRegulatoryAssetsAndLiabilities	36124000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	11525000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	12790000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	132551000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	86000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	132465000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	225130000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	383813000	USD
CY2016Q4	mgee	Deferred Tax Liabilities Equity Method Investments DeferredTaxLiabilitiesEquityMethodInvestments	71898000	USD
CY2016Q4	mgee	Deferred Tax Assets Accrued Expenses DeferredTaxAssetsAccruedExpenses	22410000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	1324000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	20304000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	344721000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	20304000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	142960000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	48860000	USD
CY2016Q4	mgee	Deferred Tax Liabilities Pension And Other Postretirement Benefits DeferredTaxLiabilitiesPensionAndOtherPostretirementBenefits	63516000	USD
CY2017Q4	mgee	Deferred Tax Liabilities Pension And Other Postretirement Benefits DeferredTaxLiabilitiesPensionAndOtherPostretirementBenefits	42919000	USD
CY2017Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	357595000	USD
CY2016Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	526773000	USD
CY2016Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	2487000	USD
CY2014Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	2365000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1924000	USD
CY2014Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	92000	USD
CY2016Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	388000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	89000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	165000	USD
CY2016	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	104000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	321000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	552000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	19000	USD
CY2016	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	39000	USD
CY2016	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	452000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	520000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	488000	USD
CY2017	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	1134000	USD
CY2016	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	532000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	845000	USD
CY2015	mgee	Unrecognized Tax Benefits Decrease Resulting From Interest Expense On Uncertain Tax Positions UnrecognizedTaxBenefitsDecreaseResultingFromInterestExpenseOnUncertainTaxPositions	102000	USD
CY2017	mgee	Unrecognized Tax Benefits Decrease Resulting From Interest Expense On Uncertain Tax Positions UnrecognizedTaxBenefitsDecreaseResultingFromInterestExpenseOnUncertainTaxPositions	312000	USD
CY2016	mgee	Unrecognized Tax Benefits Decrease Resulting From Interest Expense On Uncertain Tax Positions UnrecognizedTaxBenefitsDecreaseResultingFromInterestExpenseOnUncertainTaxPositions	27000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	1400000	USD
CY2017Q4	mgee	Unrecognized Tax Benefits Current Period Tax Positions Permanent Differences UnrecognizedTaxBenefitsCurrentPeriodTaxPositionsPermanentDifferences	100000	USD
CY2016Q4	mgee	Unrecognized Tax Benefits Current Period Tax Positions Permanent Differences UnrecognizedTaxBenefitsCurrentPeriodTaxPositionsPermanentDifferences	100000	USD
CY2015Q4	mgee	Unrecognized Tax Benefits Current Period Tax Positions Permanent Differences UnrecognizedTaxBenefitsCurrentPeriodTaxPositionsPermanentDifferences	0	USD
CY2017Q4	us-gaap	Purchase Obligation Due In Next Twelve Months PurchaseObligationDueInNextTwelveMonths	128064000	USD
CY2017Q4	us-gaap	Purchase Obligation Due In Second Year PurchaseObligationDueInSecondYear	69565000	USD
CY2017Q4	us-gaap	Purchase Obligation Due In Third Year PurchaseObligationDueInThirdYear	60348000	USD
CY2017	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1000000	USD
CY2016	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3100000	USD
CY2015	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1000000	USD
CY2017	us-gaap	Derivatives Methods Of Accounting Hedging Derivatives DerivativesMethodsOfAccountingHedgingDerivatives	<div><p style='text-align:left;margin-top:0pt;margin-bottom:0pt;line-height:12pt;' ><font style='font-family:Times New Roman;font-size:10pt;margin-left:45pt;' >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 </font><font style='font-family:Times New Roman;font-size:10pt;' >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, </font><font style='font-family:Times New Roman;font-size:10pt;' >the</font><font style='font-family:Times New Roman;font-size:10pt;' > derivatives</font><font style='font-family:Times New Roman;font-size:10pt;' > are recognized</font><font style='font-family:Times New Roman;font-size:10pt;' > in the co</font><font style='font-family:Times New Roman;font-size:10pt;' >nsolidated balance sheets at fair value</font><font style='font-family:Times New Roman;font-size:10pt;' >.</font><font style='font-family:Times New Roman;font-size:10pt;' > MGE's </font><font style='font-family:Times New Roman;font-size:10pt;' >financial commodity </font><font style='font-family:Times New Roman;font-size:10pt;' >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 man</font><font style='font-family:Times New Roman;font-size:10pt;' >agement strategies. The maximum length of time over which cash flows related to energy commodities can be hedged </font><font style='font-family:Times New Roman;font-size:10pt;' >is four</font><font style='font-family:Times New Roman;font-size:10pt;' > years. If the derivative qualifies for regulatory deferral, the derivatives are marked to fair value and are offset with a correspondin</font><font style='font-family:Times New Roman;font-size:10pt;' >g regulatory asset or liability</font><font style='font-family:Times New Roman;font-size:10pt;' > depending on whether the derivative is in a new loss or net gain position, respectively</font><font style='font-family:Times New Roman;font-size:10pt;' >. 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 </font><font style='font-family:Times New Roman;font-size:10pt;' >in electric rates as a component of the fuel rules mechanism. </font></p></div>
CY2017Q4	mgee	Counterparties In Default CounterpartiesInDefault	0
CY2017Q4	us-gaap	Purchase Obligation Due In Fourth Year PurchaseObligationDueInFourthYear	55284000	USD
CY2017Q4	us-gaap	Purchase Obligation Due In Fifth Year PurchaseObligationDueInFifthYear	42006000	USD
CY2016	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	2000000	USD
CY2017	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	1700000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	1205000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	638000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	415000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	276000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	276000	USD
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	7711000	USD
CY2016Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	26886000	USD
CY2015Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	24360000	USD
CY2017	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	145000	USD
CY2017	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	1359000	USD
CY2017	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	1789000	USD
CY2017	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	137000	USD
CY2017Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	26738000	USD
CY2016	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	1303000	USD
CY2016	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	110000	USD
CY2016	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	64000	USD
CY2016	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	1269000	USD
CY2017Q1	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	98397000	USD
CY2017Q2	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	102382000	USD
CY2017Q3	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	120761000	USD
CY2017Q4	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	92734000	USD
CY2017Q1	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	58426000	USD
CY2017Q2	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	24081000	USD
CY2017Q3	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	18778000	USD
CY2017Q4	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	47540000	USD
CY2017Q1	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	156823000	USD
CY2017Q2	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	126463000	USD
CY2017Q3	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	139539000	USD
CY2017Q4	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	140274000	USD
CY2017Q1	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	123913000	USD
CY2017Q2	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	99912000	USD
CY2017Q3	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	96538000	USD
CY2017Q4	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	114000000	USD
CY2017Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	32910000	USD
CY2017Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	26551000	USD
CY2017Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	43001000	USD
CY2017Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	26274000	USD
CY2017Q1	us-gaap	Net Income Loss NetIncomeLoss	19300000	USD
CY2017Q2	us-gaap	Net Income Loss NetIncomeLoss	15543000	USD
CY2017Q3	us-gaap	Net Income Loss NetIncomeLoss	26629000	USD
CY2017Q4	us-gaap	Net Income Loss NetIncomeLoss	36134000	USD
CY2017Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.308
CY2017Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.323
CY2017Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.308
CY2017Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.323
CY2016Q4	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	96750000	USD
CY2017Q2	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-2272000	USD
CY2017Q3	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-788000	USD
CY2017Q4	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-3533000	USD
CY2016Q4	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-1886000	USD
CY2016Q4	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	42175000	USD
CY2016Q4	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	138925000	USD
CY2016Q4	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	114967000	USD
CY2016Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	23958000	USD
CY2016Q4	us-gaap	Net Income Loss NetIncomeLoss	14502000	USD
CY2016Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.308
CY2016Q1	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	147527000	USD
CY2016Q1	us-gaap	Net Income Loss NetIncomeLoss	17028000	USD
CY2016Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	29531000	USD
CY2016Q1	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	53837000	USD
CY2016Q1	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	117996000	USD
CY2016Q1	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	93690000	USD
CY2016Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.295
CY2016Q2	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	20961000	USD
CY2016Q2	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	121576000	USD
CY2016Q2	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	100615000	USD
CY2016Q2	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	93364000	USD
CY2016Q2	us-gaap	Net Income Loss NetIncomeLoss	16150000	USD
CY2016Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	28212000	USD
CY2016Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	46527000	USD
CY2016Q3	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	136717000	USD
CY2016Q3	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	17570000	USD
CY2016Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.308
CY2016Q3	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	90190000	USD
CY2016Q3	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	119147000	USD
CY2016Q3	us-gaap	Net Income Loss NetIncomeLoss	27880000	USD
CY2017Q1	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-2443000	USD
CY2016Q3	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-2933000	USD
CY2016Q2	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-2778000	USD
CY2017Q1	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.56
CY2017Q2	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.45
CY2017Q3	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.77
CY2017Q4	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	1.04
CY2016Q1	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.49
CY2016Q2	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.47
CY2016Q3	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.80
CY2016Q4	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	0.42
CY2016Q1	mgee	Interest Expense And Other Income Net InterestExpenseAndOtherIncomeNet	-2558000	USD
CY2016Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	3443296	USD
CY2017	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	1015970	USD
CY2017	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	20400	USD
CY2017	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1304721	USD
CY2017Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	3174945	USD
CY2016	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	1195500	USD
CY2016	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	19500	USD
CY2014Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	4748657	USD
CY2016	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1465784	USD
CY2015	us-gaap	Valuation Allowances And Reserves Charged To Other Accounts ValuationAllowancesAndReservesChargedToOtherAccounts	25500	USD
CY2015	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	1675577	USD
CY2016	mgee	Fair Value Inputs Delivery Points Basis Adjustment On Peak FairValueInputsDeliveryPointsBasisAdjustmentOnPeak	0.919	pure
CY2016	mgee	Fair Value Inputs Delivery Points Basis Adjustment Off Peak FairValueInputsDeliveryPointsBasisAdjustmentOffPeak	0.934	pure
CY2017Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	4000000	USD
CY2016Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	0	USD
CY2016	mgee	Utilities Operating Expense Excluding Depreciation And Amortization UtilitiesOperatingExpenseExcludingDepreciationAndAmortization	371871000	USD
CY2017Q4	us-gaap	Margin Deposit Assets MarginDepositAssets	2500000	USD
CY2016Q4	us-gaap	Margin Deposit Assets MarginDepositAssets	1300000	USD
CY2015	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	2200000	USD
CY2017	dei	Document Type DocumentType	10-K
CY2017	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2017	dei	Entity Central Index Key EntityCentralIndexKey	0001161728
CY2017	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2017	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2017	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2017	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2017Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0.0155	pure
CY2016Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0	pure
CY2016	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Change In Unrealized Gain Loss FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	0	USD
CY2015	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Change In Unrealized Gain Loss FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	0	USD
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Other Reconciling Items Percent EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent	0.003	pure
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Other Reconciling Items Percent EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent	0.009	pure
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Other Reconciling Items Percent EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent	0	pure
CY2017Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	100000	USD
CY2015Q4	us-gaap	Assets Assets	1726403000	USD
CY2017Q4	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	100000	USD
CY2017	mgee	Operating Leases Renewal Option Term OperatingLeasesRenewalOptionTerm	P1Y
CY2017	mgee	Utilities Operating Expense Excluding Depreciation And Amortization UtilitiesOperatingExpenseExcludingDepreciationAndAmortization	381286000	USD
CY2015	mgee	Utilities Operating Expense Excluding Depreciation And Amortization UtilitiesOperatingExpenseExcludingDepreciationAndAmortization	395548000	USD
CY2017	dei	Trading Symbol TradingSymbol	MGEE
CY2015	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-20162000	USD
CY2015	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.16
CY2015	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	8613000	USD
CY2015	us-gaap	Net Income Loss NetIncomeLoss	71343000	USD
CY2015	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	112706000	USD
CY2015	us-gaap	Utilities Operating Expense Depreciation And Amortization UtilitiesOperatingExpenseDepreciationAndAmortization	44225000	USD
CY2015	us-gaap	Operating Income Loss OperatingIncomeLoss	124255000	USD
CY2015	us-gaap	Regulated And Unregulated Operating Revenue RegulatedAndUnregulatedOperatingRevenue	564028000	USD
CY2015	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Inputs Reconciliation Gain Loss Included In Earnings FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings	-6635000	USD
CY2014Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-53986000	USD
CY2016Q4	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	0	USD
CY2016Q4	mgee	Availableforsalesecuritiesgrossunrealizedlossaccumulatedininvestments Availableforsalesecuritiesgrossunrealizedlossaccumulatedininvestments	8000	USD
CY2017Q4	mgee	Availableforsalesecuritiesgrossunrealizedlossaccumulatedininvestments Availableforsalesecuritiesgrossunrealizedlossaccumulatedininvestments	46000	USD
CY2016Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	0	USD
CY2015	mgee	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresInPeriod	200000	USD
CY2015	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Non Option Equity Instruments Forfeitures ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures	4676	shares
CY2016	mgee	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresInPeriod	0	USD
CY2017	mgee	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresInPeriod	0	USD
CY2016	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Non Option Equity Instruments Forfeitures ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures	0	shares
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Non Option Equity Instruments Forfeitures ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures	0	shares
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue	5900000	USD
CY2017Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	100000	USD
CY2017Q4	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	7336000	USD
CY2016Q4	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	2020000	USD
CY2017Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	2100000	USD
CY2016Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	3700000	USD
CY2015	mgee	Regional Transmission Organization Reduction To Sales And Purchased Power Expense From Net Basis Reporting RegionalTransmissionOrganizationReductionToSalesAndPurchasedPowerExpenseFromNetBasisReporting	68600000	USD
CY2016	mgee	Regional Transmission Organization Reduction To Sales And Purchased Power Expense From Net Basis Reporting RegionalTransmissionOrganizationReductionToSalesAndPurchasedPowerExpenseFromNetBasisReporting	77200000	USD
CY2017	mgee	Regional Transmission Organization Reduction To Sales And Purchased Power Expense From Net Basis Reporting RegionalTransmissionOrganizationReductionToSalesAndPurchasedPowerExpenseFromNetBasisReporting	87900000	USD
CY2016Q4	us-gaap	Assets Held For Sale Not Part Of Disposal Group Current AssetsHeldForSaleNotPartOfDisposalGroupCurrent	14813000	USD
CY2017Q4	us-gaap	Assets Held For Sale Not Part Of Disposal Group Current AssetsHeldForSaleNotPartOfDisposalGroupCurrent	8817000	USD
CY2015	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets	484000	USD
CY2016	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets	3195000	USD
CY2017	mgee	Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets Fairvaluenetderivativeassetliabilitymeasuredonrecurringbasisunobservableinputsreconciliationgainlossincludedinregulatoryliabilitiesassets	8281000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Equity Method Investments DeferredTaxAssetsEquityMethodInvestments	31212000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Equity Method Investments DeferredTaxAssetsEquityMethodInvestments	24781000	USD
CY2016Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	355110000	USD
CY2017Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	410121000	USD
CY2017Q4	us-gaap	Purchase Obligation Due After Fifth Year PurchaseObligationDueAfterFifthYear	119619000	USD
CY2015	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	41363000	USD
CY2016	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	42513000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	22094000	USD
CY2017Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	426883000	USD
CY2016Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	9945000	USD
CY2016Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	9284000	USD
CY2016Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	15714000	USD
CY2016Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7570000	USD
CY2017Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	11167000	USD
CY2017Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	8736000	USD
CY2017Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	15584000	USD
CY2017Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-13393000	USD
CY2016Q4	us-gaap	Stockholders Equity StockholdersEquity	724088000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	778187000	USD
CY2014Q4	us-gaap	Stockholders Equity StockholdersEquity	659401000	USD
CY2017	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	108131000	USD
CY2015	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	0	USD
CY2016	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	0	USD
CY2017	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	1547000	USD
CY2017	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	70000000	USD
CY2016	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2015	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2015	us-gaap	Proceeds From Sale Of Other Property Plant And Equipment ProceedsFromSaleOfOtherPropertyPlantAndEquipment	0	USD
CY2016	us-gaap	Proceeds From Sale Of Other Property Plant And Equipment ProceedsFromSaleOfOtherPropertyPlantAndEquipment	0	USD
CY2017	us-gaap	Proceeds From Sale Of Other Property Plant And Equipment ProceedsFromSaleOfOtherPropertyPlantAndEquipment	2819000	USD
CY2016	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	83659000	USD
CY2014Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	65755000	USD
CY2015Q4	us-gaap	Stockholders Equity StockholdersEquity	690458000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	175000	USD
CY2016	us-gaap	Income Taxes Paid IncomeTaxesPaid	21831000	USD
CY2016	us-gaap	Interest Paid Net InterestPaidNet	19415000	USD
CY2016	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	16376000	USD
CY2016	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	10000000	USD
CY2017	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	43682000	USD
CY2015Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	2528000	USD
CY2016	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-70000	USD
CY2015Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	311000	USD
CY2015Q4	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis With Unobservable Inputs FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs	-53501000	USD
CY2017	us-gaap	Fair Value Net Derivative Asset Liability Measured On Recurring Basis Change In Unrealized Gain Loss FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	0	USD
CY2016Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2015	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-73313000	USD
CY2016	us-gaap	Increase Decrease In Prepaid Taxes IncreaseDecreaseInPrepaidTaxes	-8616000	USD
CY2016	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	41775000	USD
CY2016	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	147513000	USD
CY2016	us-gaap	Increase Decrease In Unbilled Receivables IncreaseDecreaseInUnbilledReceivables	4838000	USD
CY2016	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-7273000	USD
CY2016	us-gaap	Increase Decrease In Accounts And Other Receivables IncreaseDecreaseInAccountsAndOtherReceivables	3594000	USD
CY2016	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-46112000	USD
CY2016	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	14452000	USD
CY2016	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	4267000	USD
CY2016	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	1196000	USD
CY2016	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-1426000	USD
CY2016	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	9881000	USD
CY2016	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	0	USD
CY2016	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	2958000	USD
CY2016	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	5854000	USD
CY2016	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	295000	USD
CY2016	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	209000	USD
CY2016	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	14575000	USD
CY2016	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	8428000	USD
CY2016	us-gaap	Increase Decrease In Other Noncurrent Assets And Liabilities Net IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	-2695000	USD
CY2016	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	22421000	USD
CY2016	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	-700000	USD
CY2016	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	-1738000	USD
CY2015	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	2800000	USD
CY2016	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	3100000	USD
CY2017	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	3500000	USD
CY2017Q4	us-gaap	Defined Benefit Plan Expected Future Employer Contributions Next Fiscal Year DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear	0	USD
CY2017Q4	mgee	Defined Benefit Plans Expected Future Employer Contributions Year Two DefinedBenefitPlansExpectedFutureEmployerContributionsYearTwo	0	USD
CY2017Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2016	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-86826000	USD
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-116361000	USD
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	0	pure
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	0	pure
CY2017	us-gaap	Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate	0.181	pure
CY2014Q4	us-gaap	Cumulative Effect Of New Accounting Principle In Period Of Adoption CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	-142000	USD
CY2014Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest Adjusted Balance1 StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1	659259000	USD
CY2016Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	0	USD
CY2017	mgee	Immaterial Error Correction Amount ImmaterialErrorCorrectionAmount	2100000	USD
CY2015	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	2100000	USD
CY2017	us-gaap	Increase Decrease In Other Noncurrent Assets And Liabilities Net IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	-9108000	USD
CY2017Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	12244000	USD
CY2017Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	42299000	USD
CY2016Q4	us-gaap	Other Receivables Net Current OtherReceivablesNetCurrent	8530000	USD
CY2017Q4	us-gaap	Derivative Liabilities Current DerivativeLiabilitiesCurrent	8180000	USD
CY2017Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1341357000	USD

Files In Submission

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0001161728-18-000003-index-headers.html	Edgar Link	pending
0001161728-18-000003-index.html	Edgar Link	pending
0001161728-18-000003.txt	Edgar Link	pending
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Financial_Report.xlsx	Edgar Link	pending
mgee-20171231.xml	Edgar Link	completed
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mgee-20171231_cal.xml	Edgar Link	unprocessable
mgee-20171231_def.xml	Edgar Link	unprocessable
mgee-20171231_lab.xml	Edgar Link	unprocessable
mgee-20171231_pre.xml	Edgar Link	unprocessable
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$MGEE
MGE ENERGY INC Stock $mgee

2018 Q1 Form 10-K Financial Statement

#000116172818000003 Filed on February 23, 2018

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$MGEE MGE ENERGY INC Stock $mgee

2018 Q1 Form 10-K Financial Statement

#000116172818000003 Filed on February 23, 2018

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$MGEE
MGE ENERGY INC Stock $mgee