Segment Information (Schedule Of Capital Expenditures By Geographic Area) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Capital expenditures	$ 30,881	$ 16,567	$ 22,399
Americas [Member]
Segment Reporting Information [Line Items]
Capital expenditures	23,925	8,172	14,062
EMEA [Member]
Segment Reporting Information [Line Items]
Capital expenditures	5,227	5,947	7,469
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Capital expenditures	$ 1,729	$ 2,448	$ 868