Summary of Significant Accounting Policies (Reconciliation of Net Income Loss Reported in Financial Statements and Federal Tax Return) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies [Abstract]
Net income per financial statements	$ 1,462	$ 697
Adjustment to depreciation expense	131	(314)
Provision for losses and doubtful accounts	89	(85)
Adjustments to revenues / other expenses		(41)
Adjustments to gain on sales of assets	674	1,013
Other	292	(459)
Income per federal tax return (unaudited)	$ 2,648	$ 811