Schedule III (Real Estate and Accumulated Depreciation and Amortization Changes in Period) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016
Real estate
Balance at the beginning of the year	$ 276,833,694		$ 261,047,651
Acquisitions	17,560,745		23,667,535
Improvements	3,616,140		4,150,213
Impairment of real estate assets	0		(948,053)
Dispositions of real estate	(23,464,380)		(11,083,652)
Balance at the end of the year	274,546,199		276,833,694
Accumulated depreciation and amortization
Balance at the beginning of the year	(36,311,485)		(29,961,472)
Depreciation and amortization expense	(9,186,190)		(9,750,765)
Dispositions of real estate	5,485,420		3,400,752
Balance at the end of the year	$ (40,012,255)	[1]	$ (36,311,485)

[1] Depreciation is computed on a straight-line basis using useful lives up to 39 years.