Accounts Receivable - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts Receivable Roll Forward
Beginning balance	$ 6,751	$ 7,100
Bad debt provision	3,466	315	$ 1,529
Write-offs	(1,233)	(664)
Ending balance	$ 8,984	$ 6,751	$ 7,100