Goodwill And Other Intangible Assets (Schedule Of Other Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 173,858	$ 172,996
Accumulated amortization	(84,801)	(82,132)
Net carrying amount	89,057	90,864
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	100,234	100,200
Accumulated amortization	(35,992)	(34,372)
Net carrying amount	64,242	65,828
Purchased Software Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	36,156	35,328
Accumulated amortization	(29,880)	(29,612)
Net carrying amount	6,276	5,716
Technology Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	28,800	28,800
Accumulated amortization	(18,662)	(17,887)
Net carrying amount	10,138	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	(267)	(261)
Net carrying amount	$ 601	$ 607