Goodwill And Other Intangible Assets (Schedule Of Other Intangible Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 174,444	$ 172,996
Accumulated amortization	(87,198)	(82,132)
Net carrying amount	87,246	90,864
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	100,170	100,200
Accumulated amortization	(37,513)	(34,372)
Net carrying amount	62,657	65,828
Purchased Software Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	36,806	35,328
Accumulated amortization	(29,974)	(29,612)
Net carrying amount	6,832	5,716
Technology Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	28,800	28,800
Accumulated amortization	(19,438)	(17,887)
Net carrying amount	9,362	10,913
Trade Names and Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	7,800	7,800
Accumulated amortization	0	0
Net carrying amount	7,800	7,800
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	868	868
Accumulated amortization	(273)	(261)
Net carrying amount	$ 595	$ 607