| Fair Value Measurements - Financial Assets and Liabilities Carried at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands | Mar. 31, 2021 | Dec. 31, 2020 | Mar. 31, 2020 | 
|---|---|---|---|
| Transfers between Levels | |||
| Level 1 to Level 2 transfers, Assets | $ 0 | $ 0 | |
| Level 2 to Level 1 transfers, Assets | 0 | 0 | |
| Level 1 to Level 2 transfers, Liabilities | 0 | 0 | |
| Level 2 to Level 1 transfers, Liabilities | 0 | $ 0 | |
| Recurring | |||
| Assets: | |||
| Equity securities | 1,021 | $ 1,693 | |
| Liabilities: | |||
| Contingent consideration | 75 | 75 | |
| Recurring | Significant Unobservable Inputs (Level 3) | |||
| Assets: | |||
| Equity securities | 1,021 | 1,693 | |
| Liabilities: | |||
| Contingent consideration | $ 75 | $ 75 | 
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- References No definition available. 
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- Definition Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of transfers of liabilities measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- References No definition available. 
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- References No definition available. 
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- Definition Contingent consideration, fair value disclosure. No definition available. 
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- Details 
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- Details 
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