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v3.21.1

Derivative Instruments (Details) $ in Thousands | 3 Months Ended
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Mar. 31, 2021 USD ($) MWh | Mar. 31, 2020 USD ($)
Commodity Contract |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value at end of the period | $ 1,200 |
GOLDEN STATE WATER COMPANY |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Description of derivative activity volume | MWh | 445,573 |
GOLDEN STATE WATER COMPANY | Minimum | Commodity Contract |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Term of derivative contract | 3 years |
GOLDEN STATE WATER COMPANY | Maximum | Commodity Contract |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Term of derivative contract | 5 years |
Bear Valley Electric Service, Inc. | Commodity Contract |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value at beginning of the period | $ (1,537) | $ (3,171)
Unrealized gains (losses) on purchased power contracts | 2,761 | (1,109)
Fair value at end of the period | $ 1,224 | $ (4,280)

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