Goodwill And Other Intangible Assets (Schedule Of Other Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 184,463	$ 183,879
Accumulated amortization	(115,800)	(113,902)
Net carrying amount	68,663	69,977
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	100,174	100,228
Accumulated amortization	(54,961)	(53,429)
Net carrying amount	45,213	46,799
Purchased Software Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	46,820	46,183
Accumulated amortization	(33,661)	(33,307)
Net carrying amount	13,159	12,876
Technology Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	28,800	28,800
Accumulated amortization	(26,839)	(26,833)
Net carrying amount	1,961	1,967
Trade Names and Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	7,800	7,800
Net carrying amount	7,800	7,800
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	868	868
Accumulated amortization	(339)	(333)
Net carrying amount	$ 529	$ 535