Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 6,927	$ 5,706	$ 5,309
Charged to expense/against revenue	7,161	3,608	1,969
Amounts written off, net of recoveries	(1,802)	(2,387)	(1,572)
Balance at end of year	$ 12,286	$ 6,927	$ 5,706