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Derivative and Hedging Instruments (Details-5) (USD $) | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012
Counterparties in net liability position or default [Abstract] |  |
Number of counterparties in net liability position | 0 | 0
Number of counterparties in default | 0 |
Commodity Derivative Contracts [Member] | Fuel For Electric Generation Purchased Power [Member] |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Realized losses (gains) | $ (564,000) | $ 2,620,000
Commodity Derivative Contracts [Member] | Cost Of Gas Sold Expense [Member] |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Realized losses (gains) | 868,000 | 3,072,000
Financial Transmission Rights [Member] | Fuel For Electric Generation Purchased Power [Member] |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Realized losses (gains) | (983,000) | (45,000)
Financial Transmission Rights [Member] | Cost Of Gas Sold Expense [Member] |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Realized losses (gains) | 0 | 0
Ten-year PPA [Member] |  |
Derivative collateral required to be posted for ten-year PPA [Abstract] |  |
Minimum collateral that may be required to be posted | 20,000,000 |
Maximum collateral that may be required to be posted | 40,000,000 |
Collateral posted | 0 |
Ten-year PPA [Member] | Fuel For Electric Generation Purchased Power [Member] |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Realized losses (gains) | 4,209,000 | 3,232,000
Ten-year PPA [Member] | Cost Of Gas Sold Expense [Member] |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Realized losses (gains) | $ 0 | $ 0

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- Definition Minimum collateral that may be required to be posted + References No definition available. + Details
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- Definition The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44D -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624258-113959 + Details
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- Definition Net Increase or Decrease in the fair value of the derivative or group of derivatives included in earnings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959 + Details
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