Real Estate Acquisitions - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2012 sqft Apartments
Business Acquisition [Line Items]
Number of Units in Real Estate Property	49,002
Adalay Bay [Domain]
Business Acquisition [Line Items]
Number of Units in Real Estate Property	240
Legacy at Western Oaks [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property	479
Allure in Buckhead Village [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property	230
Square Footage of Real Estate Property	23,000