Accounts Receivable - Activity in Allowance for Expected Credit Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 1,880	$ 1,534	$ 1,281
Charges to income from operations	12,347	5,116	3,824
Collections from customers previously reserved and other	(12,405)	(4,770)	(3,571)
Ending balance	$ 1,822	$ 1,880	$ 1,534