Commitments and Contingencies (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($)
300 properties designed and built in violation of accessibility requirements	300
Loss Contingency Accrual, Period Increase (Decrease)	$ 1.0
Loss Contingency Accrual	$ 5.0
Projects in various stages of development	10
Units in various stages of development	3,989
Consolidated Project Under Development Commitment Fund	$ 919.5
Various stages of development with estimated completion dates ranging through September 30, 2017	Sep. 30, 2017
Number Of Unconsolidated Projects	2