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Capitalization (Schedule of Carrying Amount and Fair Value of Bonds) (Details) - USD ($) $ in Thousands | Mar. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Carrying Amount [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
First Mortgage Bonds | $ 147,209 | $ 147,667
Fair Value [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
First Mortgage Bonds | $ 159,764 | $ 159,195

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- Definition Represents the aggregate of the first mortgage bonds reported on the balance sheet at period end measured at fair value by the entity. + References No definition available. + 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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Period Type: | duration

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- Details
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Balance Type: |
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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |