Segment Information (Schedule Of Cash And Cash Equivalents By Geographic Area) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash and cash equivalents	$ 136,344	$ 184,947	$ 155,643	$ 284,862
Operating Segments [Member] | Americas [Member]
Cash and cash equivalents	51,475	105,750	98,913
Operating Segments [Member] | EMEA [Member]
Cash and cash equivalents	52,642	44,877	34,388
Operating Segments [Member] | Asia Pacific [Member]
Cash and cash equivalents	$ 32,227	$ 34,320	$ 22,342