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Derivative Instruments (Tables) | 12 Months Ended
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Dec. 31, 2017
GSWC |
Derivative instruments |
Schedule of changes in the fair value of the derivative | The following table presents changes in the fair value of GSWC’s derivatives for the years ended December 31, 2017 and 2016:
(dollars in thousands) |  | 2017 |  | 2016
Balance, at beginning of the period |  | $ | (4,901 | ) |  | $ | (7,053 | )
Unrealized gain on purchased power contracts |  | 1,960 |  |  | 2,152 |
Balance, at end of the period |  | $ | (2,941 | ) |  | $ | (4,901 | )

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- Definition Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income (loss), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset. + 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 -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19279-110258 + Details
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