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Variable Interest Entities (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019 | Dec. 31, 2015
--- | --- | --- | ---
Variable Interest Entity [Line Items] |  |  |
Contribution liability | $ 2,509,234 | $ 2,337,665 |
Cloverleaf |  |  |
Variable Interest Entity [Line Items] |  |  |
Original benefit of contribution by tax credit investor's |  |  | $ 5,600
Variable Interest Entity, Primary Beneficiary |  |  |
Variable Interest Entity [Line Items] |  |  |
Contribution liability | $ 4,800 | $ 4,900 |

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