Allowance For Doubtful Accounts - Rollforward (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 5,187	$ 5,457	$ 7,220
Charged to Costs and Expenses	1,925	493	137
Write-Offs Charged to Allowance	(322)	(295)	(2,206)
Exchange Rate Changes and Other Adjustments	4,926	(468)	306
Balance at End of Period	$ 11,716	$ 5,187	$ 5,457