Marketable Securities - Summary of Marketable Securities (Details) - USD ($)		Dec. 31, 2018	Dec. 31, 2017
Cost		$ 139,751,550	$ 121,444,694
Market Value		$ 99,595,736	$ 132,964,276
CBL & Associates Properties, Inc Preferred Stock Series D [Member]
Interest Rate		7.375%	7.375%
Number of Shares		2,000	2,000
Cost		$ 50,269	$ 50,269
Market Value		$ 21,160	$ 43,720
CBL & Associates Properties, Inc Preferred Stock Series E [Member]
Interest Rate		6.625%	6.625%
Number of Shares		62,724	62,724
Cost		$ 1,487,145	$ 1,487,145
Market Value		$ 599,641	$ 1,383,064
Cedar Realty Trust, Inc Preferred Stock Series B [Member]
Interest Rate		7.25%	7.25%
Number of Shares		8,111	18,269
Cost		$ 188,005	$ 422,544
Market Value		$ 187,023	$ 458,755
Cedar Realty Trust, Inc Preferred Stock Series C [Member]
Interest Rate		6.50%	6.50%
Number of Shares		20,000	20,000
Cost		$ 494,407	$ 494,407
Market Value		$ 379,600	$ 500,800
Colony Capital Inc. Preferred Stock Series I [Member]
Interest Rate		7.15%
Number of Shares		20,000
Cost		$ 500,000
Market Value		$ 369,000
Investors Real Estate Trust Preferred Stock Series C [Member]
Interest Rate		6.625%	6.625%
Number of Shares		20,000	20,000
Cost		$ 500,000	$ 500,000
Market Value		$ 461,684	$ 520,308
Pennsylvania Real Estate Investment Trust Preferred Stock Series B [Member]
Interest Rate		7.375%	7.375%
Number of Shares		40,000	40,000
Cost		$ 1,000,000	$ 1,000,000
Market Value		$ 654,400	$ 1,007,200
Pennsylvania Real Estate Investment Trust Preferred Stock Series D [Member]
Interest Rate		6.875%	6.875%
Number of Shares		20,000	20,000
Cost		$ 498,207	$ 498,207
Market Value		$ 310,800	$ 502,200
Urstadt Biddle Properties, Inc Preferred Stock Series G [Member]
Interest Rate		6.75%	6.75%
Number of Shares		5,000	5,000
Cost		$ 125,000	$ 125,000
Market Value		$ 123,750	$ 131,000
Urstadt Biddle Properties, Inc Preferred Stock Series H [Member]
Interest Rate		6.25%	6.25%
Number of Shares		12,500	12,500
Cost		$ 312,500	$ 312,500
Market Value		292,500	326,875
Preferred Stock [Member]
Cost		5,155,533	5,390,072
Market Value		$ 3,399,558	$ 5,377,522
CBL & Associates Properties, Inc [Member]
Number of Shares		1,600,000	1,500,000
Cost		$ 16,692,139	$ 16,157,749
Market Value		$ 3,072,000	$ 8,490,000
Franklin Street Properties Corporation [Member]
Number of Shares		220,000	150,000
Cost		$ 2,219,219	$ 1,659,118
Market Value		$ 1,370,600	$ 1,611,000
Government Properties Income Trust [Member]
Number of Shares		2,246,000	1,020,000
Cost		$ 36,418,264	$ 19,430,983
Market Value		$ 15,430,020	$ 18,910,800
Industrial Logistics Properties Trust [Member]
Number of Shares		502,258
Cost		$ 9,951,185
Market Value		$ 9,879,415
Kimco Realty Corporation [Member]
Number of Shares		910,000	750,000
Cost		$ 17,052,180	$ 14,475,908
Market Value		$ 13,331,500	$ 13,612,500
Monmouth Real Estate Investment Corporation [Member]
Number of Shares	[1]	2,446,054	2,335,930
Cost	[1]	$ 22,292,408	$ 20,698,562
Market Value	[1]	$ 30,331,065	$ 41,579,558
Pennsylvania Real Estate Investment Trust [Member]
Number of Shares		210,000	150,000
Cost		$ 2,226,089	$ 1,602,636
Market Value		$ 1,247,400	$ 1,783,500
Senior Housing Properties Trust [Member]
Number of Shares		170,911	160,911
Cost		$ 2,919,572	$ 2,739,069
Market Value		$ 2,003,078	$ 3,081,446
Tanger Factory Outlet [Member]
Number of Shares		180,000	120,000
Cost		$ 4,228,627	$ 2,941,621
Market Value		$ 3,639,600	$ 3,181,200
Urstadt Biddle Properties, Inc [Member]
Number of Shares		100,000	100,000
Cost		$ 2,048,516	$ 2,048,516
Market Value		$ 1,922,000	$ 2,174,000
Vereit, Inc [Member]
Number of Shares		1,410,000	1,300,000
Cost		$ 12,058,590	$ 11,253,514
Market Value		$ 10,081,500	$ 10,127,000
Washington Prime Group [Member]
Number of Shares		800,000	500,000
Cost		$ 6,489,228	$ 4,397,255
Market Value		3,888,000	3,560,000
Common Stock [Member]
Cost		134,596,017	116,054,622
Market Value		$ 96,196,178	$ 127,586,754
Colony Northstar, Inc. Preferred Stock Series I [Member]
Interest Rate			7.15%
Number of Shares			20,000
Cost			$ 500,000
Market Value			$ 503,600
Select Income Real Estate Investment Trust [Member]
Number of Shares			775,000
Cost			$ 18,649,691
Market Value			$ 19,475,750

[1] Related entity - See Note 8.