Accounts Receivable, Net - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Doubtful Accounts
Balance at the beginning	$ 2,641	$ 2,272	$ 14,065
Cumulative Effect of ASC 606			(9,894)
Additions	1,869	1,877	630
Reductions	(114)	(762)	(1,155)
Recoveries	(1,573)	(746)	(1,374)
Balance at the end	$ 2,823	$ 2,641	$ 2,272