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Revenue Revenue Utility Related Taxes (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
Schedule Of Utilities Operating Revenue Expense Taxes [Line Items] |  |  |
Public Utility Operating Expenses Excise Taxes Collected | $ 19,167 | $ 21,584 |
Alaska Electric Light & Power [Member] |  |  |
Schedule Of Utilities Operating Revenue Expense Taxes [Line Items] |  |  |
Public Utility Operating Expenses Excise Taxes Collected |  |  | $ 2,000

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- Definition [Line Items] for Schedule Of Utilities Operating Revenue and Expense Taxes - Utility-related taxes collected from customers and reported gross in the income statement [Table] + References No definition available. + Details
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- Details
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