Related Party Arrangements - Fees and Expenses Incurred and Reimbursable to Affiliates and Related Parties (Parenthetical) (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Related Party Transaction [Line Items]
Investment services fees	[1]	$ 545,625		$ 545,625	$ 481,500
Investment service fees capitalized		53,941,517		53,941,517		$ 31,085,939
Investment Services Fees
Related Party Transaction [Line Items]
Investment services fees		500,000	$ 0	500,000	500,000
Investment service fees capitalized		500,000	500,000	500,000	500,000
Expense Support Agreement
Related Party Transaction [Line Items]
Advisor personnel expenses		100,000	100,000	400,000	300,000
Reduction in general and administrative expenses		100,000		400,000
Asset management fees		$ 100,000	$ 43,000	$ 200,000	$ 86,000

[1] For the quarter and nine months ended September 30, 2018 the Company incurred approximately $0.5 million in investment services fees, all of which were capitalized and included in real estate investment properties, net in the accompanying condensed consolidated balance sheets. For the nine months ended September 30, 2017, the Company incurred approximately $0.5 million in investment service fees, all of which were capitalized and included in real estate investment properties, net in the accompanying condensed consolidated balance sheets. No such fees were incurred for the quarter ended September 30, 2017.