Goodwill and Other Intangible Assets (Schedule Of Components Of Other Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 74,313	$ 74,313
Accumulated Amortization	(63,913)	(63,677)
Net Carrying Amount	10,400	10,636
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	53,213	53,213
Accumulated Amortization	(52,394)	(52,319)
Net Carrying Amount	$ 819	$ 894
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	(7,219)	(7,058)
Net Carrying Amount	$ 8,181	$ 8,342
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
Licensing Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,400	$ 1,400
Net Carrying Amount	$ 1,400	$ 1,400