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Income Taxes (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Income tax benefit (expense) | $ (5,253) | $ (4,651) | $ (6,333) | $ (25,484)
Effective Tax Rate |  |  | 3.50% | 13.60%
Effective Income Tax Reconciliation, Tax Benefit From Amortization Of Excess Deferred Income Taxes |  |  | $ 2,200 |
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount |  |  | 1,900 |
Effective Income Tax Reconciliation, Tax Flow-through Benefit from Repairs and Indirect Costs |  |  | 1,100 |
Wind Assets |  |  |  |
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount |  |  | 3,200 |
Colorado Electric and Nebraska Gas |  |  |  |
Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of 2017 Amount, Tax Benefit from Bill Credit |  |  | $ 10,000 |

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