Segment Information (Textual) (Details) - 12 months ended Dec. 31, 2017 individual in Millions	Total	Property	Communities	States	individual
Segment Reporting Information [Line Items]
Number of Real Estate Properties		302	301
Number of states in which apartment units are located (states) | States				17
Market Population (individuals) | individual					1
Percentage of Total Public Multifamily REIT Units	1.00%
Period properties owned and stabilized (months)	12 months
Occupancy Level for Stabilized Communities	90.00%
Period Properties Stabilized	90 days