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Capitalization - Schedule of Carrying Amount and Fair Value of First Mortgage Bonds (FMBs) (Details) - Loans Payable - FMBs - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
FMBs	$ 126,172	$ 129,602
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
FMBs	$ 125,545	$ 125,067

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