Accounts Receivable - Allowance Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 15,072		$ 16,511
Write-offs	(4,896)	$ (2,321)	(15,939)	$ (2,321)
Additional provisions	787		787
Opening balance sheet adjustment related to ASU 2016 -13 adoption			10,097
Exchange differences	111		(382)
Ending balance	$ 11,074		$ 11,074