Name:	ede_DerivativeActualPercentageHedged
Namespace Prefix:	ede_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ede_DerivativeInstrumentProcurementGuidelinesRiskMitigationOfNaturalGasUsageGasSegmentAbstract
Namespace Prefix:	ede_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The amount of Dth hedged and held in storage.

No definition available.

Name:	ede_DerivativeNonmonetaryNotionalAmountInStorage
Namespace Prefix:	ede_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

The notional amount of financial derivatives expressed in nonmonetary units.

No definition available.

Name:	ede_DerivativeNotionalAmountNonmonetary
Namespace Prefix:	ede_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	ede_MinimumGasUsageHedgedByWinterSeasonAbstract
Namespace Prefix:	ede_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the number of future winter seasons for which minimum of expected gas usage is hedged to mitigate price volatility for the entity's customers.

No definition available.

Name:	ede_NumberOfFutureWinterSeasonsForWhichMinimumExpectedVolumeOfNaturalGasUsageIsHedged
Namespace Prefix:	ede_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the number of pipelines used to serve customers.

No definition available.

Name:	ede_NumberOfPipelinesUsedToServeCustomers
Namespace Prefix:	ede_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of storage capacity which was in place at the balance sheet date.

No definition available.

Name:	ede_PercentageOfStorageCapacityUtilized
Namespace Prefix:	ede_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Represents the percentage of storage capacity which the entity targets to have full by November 1.

No definition available.

Name:	ede_UtilizationOfStorageCapacityTargetPercentageNovember1
Namespace Prefix:	ede_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the volume of natural gas storage in pipelines that serve customers.

No definition available.

Name:	ede_VolumeOfNaturalGasStoredInPipelinesUsedToServeCustomers
Namespace Prefix:	ede_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

Name:	invest_DerivativeNonmonetaryNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4H

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44D

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_AdditionalCollateralAggregateFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44D

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: 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

Name:	us-gaap_CollateralAlreadyPostedAggregateFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_DerivativeCreditRiskRelatedContingentFeaturesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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.

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44D

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_DerivativeNetLiabilityPositionAggregateFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The percentage of expected requirements covered by the aggregate notional amount of derivative contracts expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract as a percentage of expected need.

No definition available.