Segment Information - Additional Information (Detail) - 3 months ended Mar. 31, 2019	Total	Property	States	Communities
Segment Reporting Information [Line Items]
Number of owned or owned interests of apartment communities		303		303
Number of States in which Entity Operates			17
Period properties owned and stabilized	12 months
Occupancy Level for Stabilized Communities	90.00%
Period Properties Stabilized	90 days
Same Store [Member]
Segment Reporting Information [Line Items]
Period properties owned and stabilized	12 months