Name:	ede_RateIncreaseApprovedDeferredTornadoCostsRecoveryPeriod
Namespace Prefix:	ede_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the Regulatory Asset Noncurrent Amortization Period.

No definition available.

Name:	ede_RegulatoryAssetNoncurrentAmortizationPeriod
Namespace Prefix:	ede_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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

Represents the portion of the regulatory asset expected to be recovered in future periods.

No definition available.

Name:	ede_RegulatoryAssetsExpectedRecoverableFuturePeriodAmount
Namespace Prefix:	ede_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

Amortization period for over or under recovered costs.

No definition available.

Name:	ede_UnderOrOverRecoveredCostRecoveryPeriod
Namespace Prefix:	ede_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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

The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 340

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382

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

Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost.

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

Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer.

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

The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 405

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394

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

The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period.

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

The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.24)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

Name:	ede_RegulatoryReviewProceedingsAxis=ede_RateCase2012MissouriMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_AsburyFiveYearMaintenanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_CustomerProgramsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_DeferredOperatingAndMaintenanceExpensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_IceStormAndTornadoCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_LongTermRegulatoryAssetsCurrentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_OtherRegulatoryAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_PensionAndOtherPostRetirementBenefitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_SystemReliabilityVegetationManagementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_UnamortizedLossOnInterestRateDerivativeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_UnderRecoveredElectricFuelAndPurchasedGasCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=ede_UnderRecoveredFuelCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=us-gaap_AssetRetirementObligationCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=us-gaap_DeferredIncomeTaxChargesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=us-gaap_DeferredProjectCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=us-gaap_LossOnReacquiredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=us-gaap_StormCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=ede_DeferredConstructionAccountingCostsFuelMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=ede_LongTermRegulatoryLiabilitiesCurrentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=ede_OverRecoveredElectricFuelAndPurchasedPowerCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=ede_OverRecoveredFuelCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=ede_PensionAndOtherPostRetirementBenefitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=ede_SWPAPaymentForOzakBeachLostGenerationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=ede_UnamortizedGainOnInterestRateDerivativeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=us-gaap_DeferredIncomeTaxChargesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=us-gaap_RemovalCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=ede_ElectricMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: