Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 5,706	$ 5,309	$ 4,072
Charged to expense/against revenue	3,608	1,969	2,510
Amounts written off, net of recoveries	(2,387)	(1,572)	(1,273)
Balance at end of year	$ 6,927	$ 5,706	$ 5,309