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Commitments And Contingencies (Details) - USD ($) $ in Millions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Mar. 31, 2021 | Dec. 31, 2020 | Dec. 30, 2014
Loss Contingencies [Line Items] |  |  |  |  |
Commitment for property and equipment purchases |  |  | $ 164.4 |  |
Loss contingency, damages awarded, value |  | $ 0.8 |  |  |
Loss contingency, damages awarded, attorney fees and costs |  | $ 0.5 |  |  |
May 17, 2018 Verdict [Member] |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Loss contingency, damages awarded, value | $ 92.0 |  |  |  |
Self insurance retained liability |  |  |  |  | $ 10.0
Loss contingency, estimate of possible loss |  |  | 24.9 | $ 23.6 |
Loss contingency, receivable, noncurrent |  |  | 79.2 | 79.2 |
Loss contingency, accrual, noncurrent |  |  | $ 79.2 | $ 79.2 |

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