Income Taxes (Reconciliation of Unrecognized Tax Benefits, Excluding Potential Interest and Penalties) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 5,883	$ 10,571
Gross increases - current period tax positions	7,056	520
Gross increases - tax positions in prior periods	3,243	0
Gross decreases - tax positions in prior periods	(375)	(498)
Foreign currency exchange	467	(137)
Lapse of statute of limitations	(1,709)	(4,573)
Ending balance	$ 14,565	$ 5,883