Gallons of Diesel Spilled

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- Definition

Dollar amount per megawatt of bids not subject to further investigative review.

+ References

No definition available.

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- Definition

Majority Of Bargaining Unit Employees, Percentage

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- Definition

Number Of Bargaining Unit Employees Oregon

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- Definition

Number Of Hydroelectric Plants

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- Definition

Number Of Years, License Issued

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- Definition

Percentage Of Employees, Collective Bargaining Agreement

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- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 360

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 10.C)

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 10

-Section C

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Amount of judgment or settlement awarded to (against) the entity in respect of litigation.

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- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

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- Definition

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

+ References

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

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Commitments and Contingencies Commitments and Contingencies (Details) (USD $)	1 Months Ended	12 Months Ended
	May 31, 2004	Dec. 31, 2014 employee gal hydroelectric_plant	Dec. 31, 2013	Oct. 31, 2014
Loss Contingencies [Line Items]
Investigation Reviewing	$ 250ava_InvestigationReviewing
Litigation Settlement, Amount		15,000,000us-gaap_LitigationSettlementAmount
Owners percentage interest		15.00%
Number Of Hydroelectric Plants		6ava_NumberOfHydroelectricPlants
Number Of Years, License Issued		50 years
Regulatory Assets, River Relicensing Costs		579,000,000us-gaap_RegulatoryAssets	384,355,000us-gaap_RegulatoryAssets
Gallons of Diesel Spilled		10,000ava_GallonsofDieselSpilled
Number Of Employees Covering Two Agreements		50
River Relicensing Expense [Member]
Loss Contingencies [Line Items]
Regulatory Assets, River Relicensing Costs		1,300,000
Avista Utilities [Member]
Loss Contingencies [Line Items]
Percentage Of Employees, Collective Bargaining Agreement		45.00%
Majority Of Bargaining Unit Employees, Percentage		90.00%
Alaska Electric Light & Power [Member]
Loss Contingencies [Line Items]
Percentage Of Employees, Collective Bargaining Agreement		54.00%
Investment One [Member]
Loss Contingencies [Line Items]
Other Commitment		2,800,000		3,100,000
Investment Two [Member]
Loss Contingencies [Line Items]
Other Commitment		$ 900,000