Income Taxes - Components of Income Tax Expense (Benefit) (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Current Federal alternative minimum tax ("AMT") expense	$ 8,000	$ 56,000	$ 149,000	$ 175,000
Current state and local tax expense (benefit)	(49,000)	39,000	111,000	135,000
Deferred Federal tax expense	245,000	836,000	1,490,000	3,196,000
Deferred state and local tax expense (benefit)	93,000	78,000	114,000	(394,000)
Consolidated income tax expense, including taxes attributable to discontinued operations	297,000	1,009,000	1,864,000	3,112,000
Less income tax expense attributable to discontinued operations	0	89,000	0	797,000
Income tax expense	297,000	920,000	1,864,000	2,315,000
Consolidated income tax expense, including taxes attributable to discontinued operations	$ 297,000	$ 1,009,000	$ 1,864,000	$ 3,112,000