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v3.20.2

Operations and Significant Accounting Policies - Non-Controlling Interest (Details) $ in Millions |  |  | 6 Months Ended
--- | --- | --- | ---
Apr. 29, 2020 USD ($) | Apr. 16, 2020 MW | Jun. 30, 2020 USD ($) MW | Jun. 30, 2019 USD ($)
Non-Controlling Interest Details [Line Items] |  |  |  |
Proceeds from Noncontrolling Interests | $ |  |  | $ 67.8 | $ 0.0
South Peak [Member] |  |  |  |
Non-Controlling Interest Details [Line Items] |  |  |  |
Proceeds from Noncontrolling Interests | $ | $ 67.8 |  |  |
Generating Capacity Subject to Tax Equity Financing | MW |  | 80 | 80 |
Glen Ullin Energy Center [Member] |  |  |  |
Non-Controlling Interest Details [Line Items] |  |  |  |
Generating Capacity Subject to Tax Equity Financing | MW |  |  | 106 |

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- Definition Amount of cash inflow from a noncontrolling interest. Includes, but is not limited to, purchase of additional shares or other increase in noncontrolling interest ownership. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585 + Details
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