Real Estate Acquisitions and Dispositions - Additional Information (Detail)	Jun. 30, 2016 ft² a apartmentunits Apartments
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property | apartmentunits	80,300
Cobblestone Square [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property | Apartments	314
McKinney Land [Member]
Business Acquisitions and Dispositions [Line Items]
Square Footage of Real Estate Property | ft²	30
Colonial Promenade Nord du Lac (Covington, LA) [Member]
Business Acquisitions and Dispositions [Line Items]
Square Footage of Real Estate Property	295,447
Area of Land	25
Residences at Fountainhead [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property | Apartments	322
Colonial Grand at Heathrow [Member]
Business Acquisitions and Dispositions [Line Items]
Area of Land	11
Land Title Building [Member]
Business Acquisitions and Dispositions [Line Items]
Area of Land	30,000
Colonial Promenade Huntsville [Member]
Business Acquisitions and Dispositions [Line Items]
Area of Land	1