Lease Liabilities (Components Of Lease Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease Cost [Line Items]
Total operating lease cost	$ 63	$ 62
Amortization of right of use assets	75	79
Interest on lease liabilities	5	5
Total finance lease cost	80	84
Production Costs And Taxes [Member]
Lease Cost [Line Items]
Total operating lease cost	13	13
General and Administrative [Member]
Lease Cost [Line Items]
Total operating lease cost	$ 50	$ 49