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Committed Lines of Credit - Additional Information (Details) - USD ($) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Apr. 30, 2014
Avista Utilities [Member] |  |  |
Short-term Debt [Line Items] |  |  |
Line of credit facility, maximum borrowing capacity |  |  | $ 400,000,000.0
Line of credit facility, expiration date | 2022-04 |  |
Line of credit facility additional expiration period | 1 year |  |
Line of credit facility, covenant terms, maximum debt to equity ratio | 65.00% |  |
Alaska Electric Light & Power [Member] |  |  |
Short-term Debt [Line Items] |  |  |
Line of credit facility, maximum borrowing capacity |  | $ 25,000,000.0 |
Line of credit facility, covenant terms, maximum debt to equity ratio | 67.50% |  |

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- Definition Line of credit facility additional expiration period. + References No definition available. + Details
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- Definition Line of credit facility expiration date. + References No definition available. + Details
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- Definition Line of Credit Facility, Covenant Terms, Maximum Debt to Equity Ratio + References No definition available. + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- 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
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- Details
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- Details
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