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Coronavirus Pandemic (COVID-19) - Additional Information (Detail) - COVID-19 [Member] - USD ($) $ in Millions | 9 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2021 | Dec. 31, 2020 | Mar. 27, 2020
Reimbursement of Lost Revenue |  |  | $ 100,000.0
Proceeds From Contribution In Aid Of Reimbursement of Lost Revenue | $ 7.7 | $ 22.0 |
2020 Tax Year [Member] |  |  |
Percentage of refund of income tax at the prior period corporate tax rate | 35.00% |  |
Rural Area [Member] |  |  |
Reimbursement of Lost Revenue |  |  | $ 70,000.0
Executive Officer [Member] |  |  |
Decrease In Salary | % | 50.00% |  |

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