Impairment of Long-Lived Assets - Additional Information (Detail)			3 Months Ended					9 Months Ended
	Sep. 30, 2016 USD ($) a	Sep. 16, 2016 USD ($)	Sep. 30, 2016 USD ($) a	Jun. 30, 2016 USD ($) a	Mar. 31, 2016 USD ($)	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($) property	Sep. 30, 2016 USD ($) a	Sep. 30, 2015 USD ($)
Property Plant And Equipment [Line Items]
Impairment Charges								$ 2,180,730	$ 510,041
Gain (Loss) from sale of land			$ 11,479,490			$ 3,763,140		$ 12,842,438	$ 3,781,329
Area of land | a	10,500		10,500					10,500
2016 Disposals | Sold
Property Plant And Equipment [Line Items]
Impairment Charges					$ 210,000
Gain (Loss) recognized					(134,000)
Estimated closing costs					$ 76,000
2016 Disposals | Under contract to be sold | 6 Acres of Undeveloped Land in Daytona Beach Florida [Member]
Property Plant And Equipment [Line Items]
Impairment Charges				$ 717,000
Gain (Loss) recognized				(646,000)
Estimated closing costs				$ 71,000
Area of land impairment charges recognized | a				4
Area of land | a				6
2016 Disposals | Under contract to be sold | 4 Acres of Undeveloped Land in Daytona Beach Florida [Member]
Property Plant And Equipment [Line Items]
Impairment Charges				$ 311,000
Gain (Loss) recognized				(256,000)
Estimated closing costs				55,000
Area of land impairment charges recognized | a	4		4					4
Portfolio Sale | Sold
Property Plant And Equipment [Line Items]
Gain (Loss) recognized		$ 11,100,000
2015 Disposals | Sold
Property Plant And Equipment [Line Items]
Impairment Charges							$ 510,000
Number of income properties held for sales | property							2
Gain (Loss) recognized							$ (277,000)
Estimated closing costs							$ 233,000
PNC Bank, N.A. | Altamonte Springs Florida
Property Plant And Equipment [Line Items]
Impairment Charges				942,000
Gain (Loss) from sale of land	$ (922,000)		$ 20,000
PNC Bank, N.A. | 2016 Disposals | Sold | Altamonte Springs Florida
Property Plant And Equipment [Line Items]
Impairment Charges				$ 942,000
Gain (Loss) from sale of land			$ 20,000