Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands |
9 Months Ended | 12 Months Ended | |
|---|---|---|---|
Sep. 30, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
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| Changes to the goodwill carrying value | |||
| Goodwill as of December 31, 2018 | $ 227,349 | $ 227,349 | $ 174,204 |
| Foreign exchange impact | (36) | ||
| Goodwill as of December 31, 2019 | 244,672 | 227,349 | 227,349 |
| Change in goodwill | $ 17,100 | $ 0 | |
| Zentrick And Ad-Juster | |||
| Changes to the goodwill carrying value | |||
| Business combinations | $ 53,181 | ||
| X | ||||||||||
- 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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- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits 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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- 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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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Details
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