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Common Stock - Follow-On Public Offering Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Nov. 17, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Follow-On Offering
Class of Stock [Line Items]
Proceeds from issuance of common stock		$ 295,802	$ 0	$ 0
Expenses associated with sale of stock		$ 12,898
Class B Common Stock | Follow-On Offering
Class of Stock [Line Items]
Number of shares sold (in shares)	11,500,000
Price per share sold (USD per share)	$ 32.00
Class B Common Stock | Follow-On Offering, Sold By Company
Class of Stock [Line Items]
Number of shares sold (in shares)	9,603,965
Class B Common Stock | Follow-On Offering, Exercise By Underwriters
Class of Stock [Line Items]
Number of shares sold (in shares)	1,500,000
Class B Common Stock | Follow-On Offering, Shares From Existing Shareholders
Class of Stock [Line Items]
Number of shares sold (in shares)	1,896,035
Proceeds from issuance of common stock	$ 294,429
Expenses associated with sale of stock	$ 12,898

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Stock Issuance Costs

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The cash inflow from the additional capital contribution to the entity.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

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