Intangible Assets (Schedule Of Amortization Expense For Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 45	$ 43	$ 131	$ 129
Patents
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	31	27	82	79
Software
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	6	7	22	22
Marketing assets and customer relationships
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	3	3	9	9
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 5	$ 6	$ 18	$ 19