Long-Term Debt (Schedule Of Long-Term Debt To Unrelated Entities) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Note payable to a financial institution, with interest only payment until maturity		$ 2,400
Installment notes bearing interest at the rate of 5.5% to 8.25% per annum collateralized by vehicles with monthly payments including interest, insurance and maintenance of approximately $10	$ 85	102
Total long-term debt	85	2,502
Less current maturities	(48)	(55)
Long-term debt, less current maturities	37	$ 2,447
Periodic payments including interest, insurance and maintenance	$ 10
Maximum [Member]
Debt Instrument [Line Items]
Interest rate per annum	8.25%
Minimum [Member]
Debt Instrument [Line Items]
Interest rate per annum	5.50%