Income Taxes, Continuing Operations - Deferred Tax Assets and Liabilities (Detail) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Deferred tax liabilities:
Property having a financial statement basis in excess of tax basis	$ 361,000	$ 364,000
Insurance premiums and accrued leasing revenues	16,000	29,000
Deferred tax liabilities	377,000	393,000
Deferred tax assets	(142,000)	(83,000)
Deferred tax liabilities, net of deferred tax assets	$ 235,000	$ 310,000