Goodwill and Intangible Assets, Net - Summary of Goodwill Activity (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Line Items]
Begining Balacne	$ 249,773	$ 137,121	$ 98,645
Goodwill acquired	776,147	112,356	38,515
Foreign currency translation	(28,259)	296	(39)
Ending Balacne	$ 997,661	$ 249,773	$ 137,121

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.

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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.

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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.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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