Intangible Assets (Schedule Of Amortization Expense For Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 38	$ 45	$ 119	$ 131
Patents
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	28	31	84	82
Software
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	8	6	23	22
Marketing assets and customer relationships
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	2	3	7	9
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 0	$ 5	$ 5	$ 18