Goodwill - Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Balance, beginning of period	$ 151,238	$ 151,238
Goodwill acquired during the period	11,550	0
Balance, end of period	$ 162,788	$ 151,238