Investments in Real Estate - Investments in Existing Properties (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Investments in real estate properties
Capitalized costs on existing properties	$ 44,803,561
Investments in Existing Properties
Investments in real estate properties
Capitalized costs on existing properties	12,700,000	$ 16,300,000
Re-leasing costs	1,600,000	797,000
Recurring capital expenditures	912,000	679,000
Nonrecurring building improvements	$ 10,200,000	$ 14,900,000