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Derivative Instruments (Tables) | 3 Months Ended
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Mar. 31, 2018
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, 2018 and 2017:
|  | For The Three Months Ended March 31,
(dollars in thousands) |  | 2018 |  | 2017
Fair value at beginning of the period |  | $ | (2,941 | ) |  | $ | (4,901 | )
Unrealized gain (loss) on purchased power contracts |  | 316 |  |  | (559 | )
Fair value at end of the period |  | $ | (2,625 | ) |  | $ | (5,460 | )

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- Definition Tabular disclosure of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset) using recurring unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19279-110258 + Details
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