XML 68 R49.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Fair Value of Financial Instruments (Details-2) (USD $) In Thousands, unless otherwise specified | Mar. 31, 2015 | Dec. 31, 2014
--- | --- | ---
Liabilities: |  |  |  |
Derivative liability, collateral offset | $ 600 us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset |  | $ 2,200 us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset |
Recurring [Member] |  |  |  |
Assets: |  |  |  |
Derivative assets, net | 38 us-gaap_DerivativeAssets / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 642 us-gaap_DerivativeAssets / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Total Assets | 824 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 1,569 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Liabilities: |  |  |  |
Derivative liabilities, net | 54,004 us-gaap_DerivativeLiabilities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember | [1] | 55,640 us-gaap_DerivativeLiabilities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember | [1]
Deferred compensation | 2,958 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 2,832 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Total liabilities | 56,962 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 58,472 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Recurring [Member] | Exchange Traded [Member] |  |  |  |
Assets: |  |  |  |
Available-for-sale securities | 786 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |  | 927 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |
Recurring [Member] | Level 1 [Member] |  |  |  |
Assets: |  |  |  |
Derivative assets, net | 0 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 0 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Total Assets | 786 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 927 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Liabilities: |  |  |  |
Derivative liabilities, net | 100 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember | [1] | 1,012 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember | [1]
Deferred compensation | 0 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 0 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Total liabilities | 100 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 1,012 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Recurring [Member] | Level 1 [Member] | Exchange Traded [Member] |  |  |  |
Assets: |  |  |  |
Available-for-sale securities | 786 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |  | 927 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |
Recurring [Member] | Level 2 [Member] |  |  |  |
Assets: |  |  |  |
Derivative assets, net | 0 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 0 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Total Assets | 0 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 0 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Liabilities: |  |  |  |
Derivative liabilities, net | 0 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember | [1] | 0 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember | [1]
Deferred compensation | 2,958 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 2,832 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Total liabilities | 2,958 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 2,832 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Recurring [Member] | Level 2 [Member] | Exchange Traded [Member] |  |  |  |
Assets: |  |  |  |
Available-for-sale securities | 0 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |  | 0 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |
Recurring [Member] | Level 3 [Member] |  |  |  |
Assets: |  |  |  |
Derivative assets, net | 38 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 642 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Total Assets | 38 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 642 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Liabilities: |  |  |  |
Derivative liabilities, net | 53,904 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember | [1] | 54,628 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember | [1]
Deferred compensation | 0 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 0 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Total liabilities | 53,904 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |  | 54,628 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember |
Recurring [Member] | Level 3 [Member] | Exchange Traded [Member] |  |  |  |
Assets: |  |  |  |
Available-for-sale securities | 0 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |  | 0 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |
MGE [Member] |  |  |  |
Liabilities: |  |  |  |
Derivative liability, collateral offset | 600 us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 2,200 us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
MGE [Member] | Recurring [Member] |  |  |  |
Assets: |  |  |  |
Derivative assets, net | 38 us-gaap_DerivativeAssets / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 642 us-gaap_DerivativeAssets / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Total Assets | 252 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 992 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Liabilities: |  |  |  |
Derivative liabilities, net | 54,004 us-gaap_DerivativeLiabilities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [1] | 55,640 us-gaap_DerivativeLiabilities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [1]
Deferred compensation | 2,958 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 2,832 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Total liabilities | 56,962 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 58,472 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
MGE [Member] | Recurring [Member] | Exchange Traded [Member] |  |  |  |
Assets: |  |  |  |
Available-for-sale securities | 214 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |  | 350 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |
MGE [Member] | Recurring [Member] | Level 1 [Member] |  |  |  |
Assets: |  |  |  |
Derivative assets, net | 0 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 0 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Total Assets | 214 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 350 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Liabilities: |  |  |  |
Derivative liabilities, net | 100 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [1] | 1,012 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [1]
Deferred compensation | 0 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 0 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Total liabilities | 100 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 1,012 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
MGE [Member] | Recurring [Member] | Level 1 [Member] | Exchange Traded [Member] |  |  |  |
Assets: |  |  |  |
Available-for-sale securities | 214 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |  | 350 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |
MGE [Member] | Recurring [Member] | Level 2 [Member] |  |  |  |
Assets: |  |  |  |
Derivative assets, net | 0 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 0 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Total Assets | 0 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 0 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Liabilities: |  |  |  |
Derivative liabilities, net | 0 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [1] | 0 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [1]
Deferred compensation | 2,958 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 2,832 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Total liabilities | 2,958 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 2,832 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
MGE [Member] | Recurring [Member] | Level 2 [Member] | Exchange Traded [Member] |  |  |  |
Assets: |  |  |  |
Available-for-sale securities | 0 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |  | 0 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |
MGE [Member] | Recurring [Member] | Level 3 [Member] |  |  |  |
Assets: |  |  |  |
Derivative assets, net | 38 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 642 us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Total Assets | 38 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 642 us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Liabilities: |  |  |  |
Derivative liabilities, net | 53,904 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [1] | 54,628 us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [1]
Deferred compensation | 0 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 0 mgee_DeferredCompensationFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Total liabilities | 53,904 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 54,628 us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
MGE [Member] | Recurring [Member] | Level 3 [Member] | Exchange Traded [Member] |  |  |  |
Assets: |  |  |  |
Available-for-sale securities | $ 0 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |  | $ 0 us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = us-gaap_SubsidiariesMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember |
[1] | These amounts are shown gross and exclude $0.6 and $2.2 million of collateral that was posted against derivative positions with counterparties as of March 31, 2014 and December 31, 2014, respectively.

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