Real Estate Acquisitions and Dispositions - Additional Information (Detail)	3 Months Ended	0 Months Ended		1 Months Ended
	Mar. 31, 2015 Communities	Apr. 29, 2015 Communities apartmentunits	Apr. 01, 2015 Communities apartmentunits	Apr. 29, 2015 Communities apartmentunits
Business Acquisitions and Dispositions [Line Items]
Number Of Properties Sold	1
Number of Properties Held for Sale	17
Number of Units in Real Estate Property	81,976
River's Walk [Member]
Business Acquisitions and Dispositions [Line Items]
Area of Land	1.9
Residences at Burlington Creek [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property	298
Vistas [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property	144
Austin Chase [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property	256
Fairways At Hartland [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property	240
Fountain Lake [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property	113
Disposal Group, Not Discontinued Operations [Member]
Business Acquisitions and Dispositions [Line Items]
Number Of Properties Sold	4
Subsequent Event [Member]
Business Acquisitions and Dispositions [Line Items]
Number Of Properties Sold		10	4	14
Number of Units in Real Estate Property		2,110	640	2,110