Income Tax Considerations (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Impairment loss	$ 4,692	$ 4,732
Net operating loss carryforwards	3,206	11,132
Straight-line rentals	0	1,391
Book-tax basis differential	1,101	1,800
Other	177	201
Total deferred tax assets	9,176	19,256
Valuation allowance	(5,749)	(12,787)
Total deferred tax assets, net of allowance	3,427	6,469
Deferred tax liabilities:
Book-tax basis differential	1,547	6,005
Other	155	398
Total deferred tax liabilities	1,702	$ 6,403
Deferred tax assets, operating loss carryforwards, not subject to expiration	$ 15,300