Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands |
9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Goodwill and Intangible Assets | ||||
| Goodwill | $ 244,672 | $ 227,349 | $ 227,349 | $ 174,204 |
| Change in goodwill | $ 17,100 | $ 0 |
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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- Definition Amount of increase (decrease) of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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