Income Taxes - Valuation Allowance Rollforward (Details) - Valuation Allowance of Deferred Tax Assets [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances, Beginning Balance	$ 7,401	$ 6,344	$ 6,259
Additional Valuation Allowance	650	1,127	294
Allowance Utilization and Other	(471)	(61)	(187)
Effect of Exchange Rate Changes	(60)	(9)	(22)
Valuation Allowance, Ending Balance	$ 7,520	$ 7,401	$ 6,344