Fair Value Measurements - Summary of Fair Value of Level 3 Financial Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, at the beginning of the period	$ 1,706,470
Fair value, at the end of the period	1,322,830
Fair Value Inputs Level3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, at the beginning of the period	35,100	$ 30,000
Additions	1,800	0
Changes in estimated fair value	4,488	0
Fair value, at the end of the period	$ 32,412	$ 30,000