Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reserves For Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 5,128	$ 4,306	$ 3,533
Charges to Costs and Expenses	822	2,200	2,035
Write-Offs/Cash Payments	(531)	(817)	(1,146)
Foreign Currency Translation	(896)	(561)	(116)
Balance at End of Year	4,523	5,128	4,306
Valuation Allowance For Deferred Tax [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	4,446	4,678	5,201
Charges to Costs and Expenses	885	634	799
Write-Offs/Cash Payments	(816)	(468)	(1,042)
Foreign Currency Translation	376	(398)	(280)
Balance at End of Year	$ 4,891	$ 4,446	$ 4,678