Long-Term Debt (Schedule Of Long-Term Debt To Unrelated Entities) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Note payable to a financial institution, with interest only payment until maturity
Installment notes bearing interest at the rate of 4.16% to 4.60% per annum collateralized by vehicles with monthly payments including interest, insurance and maintenance of approximately $5	136	90
Total long-term debt	136	90
Less current maturities	(60)	(41)
Long-term debt, less current maturities	76	$ 49
Periodic payments including interest, insurance and maintenance	$ 5
Maximum [Member]
Debt Instrument [Line Items]
Interest rate per annum	4.60%
Minimum [Member]
Debt Instrument [Line Items]
Interest rate per annum	4.16%