Common Stock - Additional Information (Details) $ in Thousands		1 Months Ended	3 Months Ended	9 Months Ended		12 Months Ended
	Jan. 20, 2021 USD ($) shares	May 31, 2020 USD ($) shares	Mar. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) shares	Jan. 19, 2021 common_stock_class
Class of Stock [Line Items]
Number of classes of common stock | common_stock_class							2
Payments for repurchase of common stock				$ 22,027	$ 0
Pre-closing stock repurchase, net of exercise of vested options			$ 21,902
Repurchase of Stock | Former Executive Officer
Class of Stock [Line Items]
Notes receivable, amount of principal payment canceled		$ 900
Common Class A
Class of Stock [Line Items]
Pre-closing stock repurchase, net of exercise of vested options (in shares) | shares	183,548	509,602				85,594
Payments for repurchase of common stock	$ 22,000					$ 100
Stock repurchased and retired during period (in shares) | shares	2,207,580
Pre-closing stock repurchase, net of exercise of vested options	$ 1,800