Commitments and Contingencies - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($) Property ApartmentUnit
Accrual for Environmental Loss Contingencies | $	$ 5.7
Number of properties with environmental reserves | Property	2
Loss Contingency Accrual | $	$ 0.9
Projects in various stages of development | Property	4
Units in various stages of development | ApartmentUnit	1,285
Consolidated Project Under Development Commitment Fund | $	$ 127.3
Various stages of development with estimated completion dates ranging through September 30, 2017	Sep. 30, 2019
Partially Owned Properties – Unconsolidated
Number Of Unconsolidated Projects | Property	2