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]
Allowance for doubtful accounts, beginning balance	$ 7,562	$ 4,404	$ 1,940
Accounts written off during the year	(6,208)	(1,144)	(310)
Recoveries	(701)	(177)	(316)
Bad debt expense	4,001	4,479	3,090
Allowance for doubtful accounts, period increase (decrease)	3,300	4,302	2,774
Allowance for doubtful accounts, ending balance	$ 4,654	$ 7,562	$ 4,404