Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reserves for doubtful accounts receivable
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 4,576	$ 4,523	$ 5,128
Charges to Costs and Expenses	390	591	822
Write-Offs/Cash Payments	(969)	(1,660)	(531)
Foreign Currency Translation	705	1,122	(896)
Balance at End of Year	4,702	4,576	4,523
Valuation allowance for deferred tax assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	6,211	4,891	4,446
Charges to Costs and Expenses	402	1,789	885
Write-Offs/Cash Payments	0	(679)	(816)
Foreign Currency Translation	(401)	210	376
Balance at End of Year	$ 6,212	$ 6,211	$ 4,891