Accounts Receivable - Accounts Receivable, Expected Credit Loss (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses as of January 1,	$ (6,632)	$ (5,081)
Credit loss expense	(1,929)	(1,633)
Credit loss income and utilization	1,989	601
Foreign currency translation effects	193	519
Allowance for credit losses as of June 30,	$ (6,379)	$ (5,594)