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Common Stock - Initial Public Offering and Authorized Common Shares Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 12 Months Ended |
--- | --- | --- | ---
Sep. 25, 2020 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Apr. 20, 2018
Class of Stock [Line Items] |  |  |  |  |
Payments of expenses associated with initial public offering |  | $ 1,373 | $ 0 | $ 0 |
Public Stock Offering - Shares From Existing Shareholders |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Payments of expenses associated with initial public offering |  | $ 26,130 |  |  |
Class B Common Stock |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Common stock shares authorized (up to) (in shares) | 1,800,000,000 | 1,800,000,000 |  |  | 600,000,000
Common stock shares outstanding (in shares) |  | 260,552,747 | 243,241,192 |  |
Class B Common Stock | Public Stock Offering - Shares From Existing Shareholders |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Number of shares sold (in shares) | 12,360,991 |  |  |  |
Price per share sold (USD per share) | $ 22.00 |  |  |  |
Class A Common Stock |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Common stock shares authorized (up to) (in shares) | 100,000,000 | 100,000,000 |  |  | 320,000,000
Common stock shares outstanding (in shares) |  | 11,601,757 | 11,601,757 |  |

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