Real Estate Disposition Activities (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) community land_parcel	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) community land_parcel home	Jun. 30, 2015 USD ($)
Summary of income from discontinued operations
Number of Apartment Communities Sold | community			2
Gain on sale of communities	$ 30,990	$ 0	$ 82,420	$ 70,936
Number of Communities Held for Sale | community	1		1
Number of Land Parcels Held For Sale | land_parcel	4		4
Eaves Trumbull [Member]
Summary of income from discontinued operations
Apartment homes | home			340
Proceeds from Sale of Real Estate			$ 70,250
Gain on sale of communities			$ 51,430
Avalon Essex [Member]
Summary of income from discontinued operations
Apartment homes | home			154
Proceeds from Sale of Real Estate			$ 45,100
Gain on sale of communities			$ 31,081