Energy Sales, Soft-Cap Price Threshold

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The number of demand rates in the Class A rate schedule for electric power sales to Members.

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The number of billing components in the Class A rate schedule for electric power sales to Members.

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Number Of Utility Members

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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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.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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REVENUE - Narrative (Details) $ in Thousands	12 Months Ended
REVENUE - Narrative (Details) $ in Thousands	Dec. 31, 2023 USD ($) billing_component demand_rate utility_member	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Aug. 31, 2020 $ / MWh
Disaggregation of Revenue [Line Items]
Number of utility members \| utility_member	42
Number of billing components of Class A rate schedule for electric power sales to Members \| billing_component	3
Number of demand rates \| demand_rate	2
Soft-cap price for short term spot market sales (per megawatt hour) \| $ / MWh				1,000
Member electric sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 1,208,352	$ 1,213,234	$ 1,161,291
Rate stabilization
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	47,127	$ 95,613	$ 78,457
United Power, Inc.
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 237,200
United Power, Inc. \| Revenue Benchmark \| Customer Concentration
Disaggregation of Revenue [Line Items]
Concentration risk (as a percent)	16.20%
United Power, Inc. \| Member electric sales \| Revenue Benchmark \| Customer Concentration
Disaggregation of Revenue [Line Items]
Concentration risk (as a percent)	19.60%