Real Estate Acquisitions and Dispositions - Additional Information (Details)	Sep. 30, 2017 a apartmentunits	Mar. 31, 2017 apartmentunits
Charlotte at MIdtown [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property | apartmentunits		279
Colonial Grand at Lakewood Ranch [Member]
Business Acquisitions and Dispositions [Line Items]
Area of Land | a	12
Paddock Club Lakeland [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property | apartmentunits	464
Area of Land | a	9
Northwood [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property | apartmentunits	270
Town Park Lot [Member]
Business Acquisitions and Dispositions [Line Items]
Area of Land | a	1
Paddock Club Montgomery [Member]
Business Acquisitions and Dispositions [Line Items]
Number of Units in Real Estate Property | apartmentunits	208
Post Alexander [Member]
Business Acquisitions and Dispositions [Line Items]
Area of Land | a	1