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Derivative Instruments (Tables) | 3 Months Ended
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Mar. 31, 2017
GOLDEN STATE WATER COMPANY |
Derivative Instruments, Gain (Loss) [Line Items] |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation | The following table presents changes in the fair value of GSWC’s Level 3 derivatives for the three months ended March 31, 2017 and 2016:
(dollars in thousands) |  | 2017 |  | 2016
Fair value at beginning of the period |  | $ | (4,901 | ) |  | $ | (7,053 | )
Unrealized loss on purchased power contracts |  | (559 | ) |  | (192 | )
Fair value at end of the period |  | $ | (5,460 | ) |  | $ | (7,245 | )

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