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Derivative and Hedging Instruments (Details-4) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2015 | Dec. 31, 2014
Current and Long-Term Regulatory Asset [Member] |  |
Change in Derivative Fair Value [Roll Forward] |  |
Beginning balance | $ 54,998 | $ 63,893
Unrealized loss (gain) | 8,586 | (14,518)
Realized (loss) gain reclassified to a deferred account | (2,953) | 595
Realized (loss) gain reclassified to income statement | (6,549) | 5,028
Ending balance | 54,082 | 54,998
Other Current Assets [Member] |  |
Change in Derivative Fair Value [Roll Forward] |  |
Beginning balance | 1,001 | 411
Unrealized loss (gain) | 0 | 0
Realized (loss) gain reclassified to a deferred account | 2,953 | (595)
Realized (loss) gain reclassified to income statement | (2,746) | 1,185
Ending balance | $ 1,208 | $ 1,001

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- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13433-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13495-108611 + Details
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