Related Party Arrangements - Narrative - Disposition Fee (Details)	12 Months Ended
	Dec. 31, 2018 $ / shares
Related Party Transaction [Line Items]
Other operating expense reimbursement, percentage of average invested assets, threshold	2.00%
Other operating expense reimbursement, percentage of net income, threshold	25.00%
Advisor [Member] | Advisor [Member] | Disposition Fee [Member]
Related Party Transaction [Line Items]
Disposition fee, percent of sales price	1.50%
Disposition fee, maximum, percentage of sales price	3.00%
Acquisition fees and expenses, maximum, percentage of contract purchase price	6.00%
Disposition fee, maximum brokerage commission paid, percent	50.00%
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 1 [Member]
Related Party Transaction [Line Items]
Disposition fee, percent of sales price	0.50%
Share price (in dollars per share)	$ 9.00
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 2 [Member]
Related Party Transaction [Line Items]
Disposition fee, percent of sales price	0.75%
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 2 [Member] | Minimum [Member]
Related Party Transaction [Line Items]
Share price (in dollars per share)	$ 9.01
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 2 [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Share price (in dollars per share)	$ 10.24
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 3 [Member]
Related Party Transaction [Line Items]
Disposition fee, percent of sales price	1.00%
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 3 [Member] | Minimum [Member]
Related Party Transaction [Line Items]
Share price (in dollars per share)	$ 10.25
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 3 [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Share price (in dollars per share)	$ 11.24
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 4 [Member]
Related Party Transaction [Line Items]
Disposition fee, percent of sales price	1.25%
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 4 [Member] | Minimum [Member]
Related Party Transaction [Line Items]
Share price (in dollars per share)	$ 11.25
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 4 [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Share price (in dollars per share)	$ 12.00
Advisor [Member] | Advisor [Member] | Disposition Fee, Range 5 [Member]
Related Party Transaction [Line Items]
Disposition fee, percent of sales price	1.50%
Share price (in dollars per share)	$ 12.01
Advisor [Member] | Advisor [Member] | Other Operating Expenses [Member]
Related Party Transaction [Line Items]
Other operating expense reimbursement, percentage of average invested assets, threshold	2.00%
Other operating expense reimbursement, percentage of net income, threshold	25.00%