Trade Receivables - Allowance for Doubtful Accounts Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
January 1	$ (16,068)	$ (25,918)
Allowance for credit losses through retained earnings	(6,997)	(5,282)
Reversal of provision	2,989	5,931
Currency translation adjustment	490	100
March 31	(23,084)	$ (25,169)
Cumulative Effect, Period Of Adoption, Adjustment
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
January 1	$ 3,498