Real Estate and Lease Intangibles - Real Estate Acquisitions and Dispositions (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($) Property ApartmentUnit
Properties acquired | Property	4
Property Units acquired | ApartmentUnit	947
Purchase Price	$ 468,050
Properties disposed | Property	4
Property Units disposed | ApartmentUnit	1,024
Sales Price	$ 353,150
Rental Properties – Consolidated [Member]
Properties acquired | Property	4
Property Units acquired | ApartmentUnit	947
Purchase Price	$ 468,050
Properties disposed | Property	4
Property Units disposed | ApartmentUnit	1,024
Sales Price	$ 319,700
Land [Member]
Purchase Price	68,300
Sales Price	$ 33,450