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Risk Management and Derivatives: Cash Flow Hedges (Details) - Cash Flow Hedging - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2022 | Mar. 31, 2021
Interest Rate Swap and Commodity Derivative |  |
Derivative [Line Items] |  |
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months | $ 1,800 |
Designated as Hedging Instrument |  |
Derivative [Line Items] |  |
Unrealized Gain (Loss) on Cash Flow Hedging Instruments | (154) | $ 886
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net | 1,541 | (744)
Designated as Hedging Instrument | Interest rate swaps |  |
Derivative [Line Items] |  |
Unrealized Gain (Loss) on Cash Flow Hedging Instruments | 713 | 713
Designated as Hedging Instrument | Interest rate swaps | Interest Expense |  |
Derivative [Line Items] |  |
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net | (713) | (713)
Designated as Hedging Instrument | Commodity Contract |  |
Derivative [Line Items] |  |
Unrealized Gain (Loss) on Cash Flow Hedging Instruments | (867) | 173
Designated as Hedging Instrument | Commodity Contract | Fuel, purchased power and cost of natural gas sold |  |
Derivative [Line Items] |  |
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net | $ 2,254 | $ (31)

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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=125515794&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=125515794&loc=SL5624171-113959 + Details
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- Definition Amount of unrealized gain (loss) related to derivatives designated as cash flow hedging instruments, recorded in results of operations to the extent that the cash flow hedge is determined to be ineffective. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5624171-113959 + Details
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