Business and Organization - Schedule of Properties Under Development or Construction (Details)	12 Months Ended
Dec. 31, 2017
Harding Place
Business and Organization
Preferred return	9.00%
Brooks Crossing
Business and Organization
Preferred return	8.00%
Mixed-use \| Town Center Phase VI
Business and Organization
Ownership interest percentage in property	100.00%
Multifamily \| Harding Place
Business and Organization
Ownership interest percentage in property	80.00%
Multifamily \| 595 King Street
Business and Organization
Ownership interest percentage in property	92.50%
Multifamily \| 530 Meeting Street
Business and Organization
Ownership interest percentage in property	90.00%
Office \| Brooks Crossing
Business and Organization
Ownership interest percentage in property	65.00%

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant