Segment Information (Schedule Of Long-Lived Assets By Geographic Area) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Long-lived assets	$ 458,342	$ 416,203	$ 459,492
Operating Segments [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Long-lived assets	94,319	96,016	113,364
Operating Segments [Member] | EMEA [Member]
Segment Reporting Information [Line Items]
Long-lived assets	306,988	262,543	285,980
Operating Segments [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Long-lived assets	$ 57,035	$ 57,644	$ 60,148