Number of counterparites in default as of the balance sheet date.

No definition available.

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- Details

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- Details

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- Definition

Maximum collateral that may be required to be posted.

+ References

No definition available.

+ Details

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- Definition

Minimum collateral that may be required to be posted.

+ References

No definition available.

+ Details

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- 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=7476318&loc=SL5624258-113959

+ Details

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- 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=7476318&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=7476318&loc=SL5624171-113959

+ Details

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- 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=7476318&loc=SL5624258-113959

+ Details

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- Details

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Derivative and Hedging Instruments (Details-5) (USD $)	3 Months Ended
Derivative and Hedging Instruments (Details-5) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Counterparties in net liability position or default [Abstract]
Derivative, net liability position of counterparties (less than $0.1 million)	$ 100,000		$ 100,000
Number of counterparties in default	0mgee_CounterpartiesInDefault
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	420,000	(4,795,000)
Commodity Derivative Contracts [Member] \| Cost Of Gas Sold Expense [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	1,761,000	(1,220,000)
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	(119,000)	(636,000)
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
Purchased Power Agreement [Member]
Derivative collateral required to be posted for ten-year PPA [Abstract]
Minimum collateral that may be required to be posted	20,000,000
Maximum collateral that may be required to be posted	40,000,000
Collateral posted	0
Purchased Power Agreement [Member] \| Fuel For Electric Generation Purchased Power [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	1,021,000	(1,210,000)
Purchased Power Agreement [Member] \| Cost Of Gas Sold Expense [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	$ 0	$ 0