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Risk Management and Derivatives: Derivatives Designated as Hedges (Details) - Cash Flow Hedging - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Derivative [Line Items] |  |  |  |
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net | $ (890) | $ (842) | $ (2,872) | $ (1,631)
Designated as Hedging Instrument |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net | 1,403 | 692 | 3,097 | 1,197
Natural Gas, Distribution |  |  |  |
Derivative [Line Items] |  |  |  |
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months |  |  | 100 |
Interest rate swaps | Designated as Hedging Instrument |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net | 712 | 713 | 2,138 | 2,139
Commodity Contracts | Designated as Hedging Instrument |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net | 691 | (21) | 959 | (942)
Interest expense | Interest rate swaps |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net | (712) | (713) | (2,138) | (2,139)
Fuel, purchased power and cost of natural gas sold | Commodity Contracts |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net | $ (178) | $ (129) | $ (734) | $ 508

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- Definition The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121549185&loc=d3e80748-113994 + Details
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- Definition The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4D -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624177-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624171-113959 + Details
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