Goodwill and Other Intangible Assets (Schedule Of Components Of Other Intangible Assets) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 75,963	$ 75,962
Accumulated Amortization	(65,174)	(64,640)
Net Carrying Amount	10,789	11,322
Licensing Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,400	1,400
Net Carrying Amount	1,400	1,400
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	54,863	54,862
Accumulated Amortization	(52,853)	(52,640)
Net Carrying Amount	$ 2,010	$ 2,222
Useful Lives (in years)	11 years	11 years
Trade names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 15,400	$ 15,400
Accumulated Amortization	(8,021)	(7,700)
Net Carrying Amount	$ 7,379	$ 7,700
Useful Lives (in years)	24 years	24 years
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 4,300	$ 4,300
Accumulated Amortization	(4,300)	(4,300)
Net Carrying Amount	$ 0	$ 0
Useful Lives (in years)	10 years	10 years