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v3.8.0.1

SUBSEQUENT EVENTS (Details) - USD ($) $ in Thousands | 1 Months Ended |  |
--- | --- | --- | ---
Jan. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Subsequent Event [Line Items] |  |  |
Principal amount |  | $ 106,931 | $ 103,647
First Mortgage Bonds [Member] |  |  |
Subsequent Event [Line Items] |  |  |
Principal amount |  | $ 99,600 | $ 95,600
Subsequent Event [Member] | First Mortgage Bonds [Member] |  |  |
Subsequent Event [Line Items] |  |  |
Principal amount | $ 25,000 |  |
Subsequent Event [Member] | First Mortgage Bonds [Member] | Series U [Member] |  |  |
Subsequent Event [Line Items] |  |  |
Principal amount | $ 25,000 |  |
Maturity date | Jan. 31, 2038 |  |
Interest rate, stated percentage | 4.71% |  |

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- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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