XML 110 R88.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Derivative and Hedging Instruments (Details-5) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2015 USD ($) counterparty | Dec. 31, 2014 USD ($)
Counterparties in net liability position or default [Abstract] |  |
Derivative, net liability position of counterparties (less than $0.1 million) | $ 100 | $ 100
Number of counterparties in default | counterparty | 0 |
Commodity Derivative Contracts [Member] | Fuel For Electric Generation Purchased Power [Member] |  |
Realized losses (gains) on income statement [Line Items] |  |
Realized losses (gains) on income statement | $ 2,236 | (5,515)
Commodity Derivative Contracts [Member] | Cost Of Gas Sold Expense [Member] |  |
Realized losses (gains) on income statement [Line Items] |  |
Realized losses (gains) on income statement | 2,548 | (1,103)
Financial Transmission Rights [Member] | Fuel For Electric Generation Purchased Power [Member] |  |
Realized losses (gains) on income statement [Line Items] |  |
Realized losses (gains) on income statement | (309) | (1,110)
Financial Transmission Rights [Member] | Cost Of Gas Sold Expense [Member] |  |
Realized losses (gains) on income statement [Line Items] |  |
Realized losses (gains) on income statement | 0 | 0
PPA [Member] |  |
Derivative collateral required to be posted for ten-year PPA [Abstract] |  |
Minimum collateral that may be required to be posted | 20,000 |
Maximum collateral that may be required to be posted | 40,000 |
Collateral posted | 0 |
PPA [Member] | Fuel For Electric Generation Purchased Power [Member] |  |
Realized losses (gains) on income statement [Line Items] |  |
Realized losses (gains) on income statement | 4,820 | 1,515
PPA [Member] | Cost Of Gas Sold Expense [Member] |  |
Realized losses (gains) on income statement [Line Items] |  |
Realized losses (gains) on income statement | $ 0 | $ 0

X
- Definition Number of counterparites in default as of the balance sheet date. + References No definition available. + Details
Name: | mgee_CounterpartiesInDefault
Namespace Prefix: | mgee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | mgee_CounterpartiesInNetLiabilityPositionOrDefaultAbstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | mgee_DerivativeCollateralRequiredToPostAbstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum collateral that may be required to be posted. + References No definition available. + Details
Name: | mgee_DerivativeCollateralRequiredToPostMaximum
Namespace Prefix: | mgee_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Minimum collateral that may be required to be posted + References No definition available. + Details
Name: | mgee_DerivativeCollateralRequiredToPostMinimum
Namespace Prefix: | mgee_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624258-113959 + Details
Name: | us-gaap_CollateralAlreadyPostedAggregateFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5618551-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959 + Details
Name: | us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DerivativeInstrumentsGainLossLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624258-113959 + Details
Name: | us-gaap_DerivativeNetLiabilityPositionAggregateFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=mgee_FuelForElectricGenerationPurchasedPowerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=mgee_CostOfGasSoldExpenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=mgee_FinancialTransmissionRightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=mgee_PurchasedPowerAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |