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Commitments and Contingencies - Additional Information (Details) - USD ($) | Aug. 19, 2019 | Jun. 30, 2020 | Mar. 06, 2020 | Dec. 31, 2019
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Loss Contingencies [Line Items] |  |  |  |
Regulatory liabilities |  | $ 49,629,000 |  | $ 51,715,000
Boyds Fire [Member] | Damage from Fire [Member] | Maximum [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Loss contingency, damages sought, value | $ 4,400,000 |  |  |
Provision for Rate Refunds [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Regulatory liabilities |  | $ 7,339,000 | $ 8,500,000 | $ 3,565,000
Provision for Rate Refunds [Member] | Electricity [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Regulatory liabilities |  |  | 4,900,000 |
Provision for Rate Refunds [Member] | Natural Gas [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Regulatory liabilities |  |  | $ 3,600,000 |

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