Business of Organization - Additional Information (Details) - property	Jun. 30, 2018	Dec. 31, 2017
Business And Organization [Line Items]
Percentage of Operating Partnership held	73.80%	72.00%
General Partner
Business And Organization [Line Items]
Percentage of Operating Partnership held	0.10%
Operating Property
Business And Organization [Line Items]
Number of real estate properties	49
Development Property
Business And Organization [Line Items]
Number of real estate properties	8