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Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2019 | Mar. 31, 2021 | Dec. 31, 2020
Assets and liabilities measured at fair value on a recurring basis |  |  |
Marketable securities in deferred compensation plan |  | $ 3,019 | $ 3,027
Fair value measurement on a recurring basis | Deferred compensation plan | Trustees and Management |  |  |
Assets and liabilities measured at fair value on a recurring basis |  |  |
Maximum percentage of participants' compensation which is deferrable | 100.00% |  |
Marketable securities in deferred compensation plan |  | $ 3,000 |

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