Goodwill And Other Intangible Assets (Schedule Of Other Intangible Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 175,275	$ 172,996
Accumulated amortization	(89,852)	(82,132)
Net carrying amount	85,423	90,864
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	100,162	100,200
Accumulated amortization	(39,091)	(34,372)
Net carrying amount	61,071	65,828
Purchased Software Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	37,645	35,328
Accumulated amortization	(30,268)	(29,612)
Net carrying amount	7,377	5,716
Technology Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	28,800	28,800
Accumulated amortization	(20,214)	(17,887)
Net carrying amount	8,586	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	(279)	(261)
Net carrying amount	$ 589	$ 607