Real Estate - Disposed Properties to Unaffiliated Parties (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Property ApartmentUnit	Dec. 31, 2018 USD ($) Property ApartmentUnit
Properties disposed | Property	13	5
Property Units disposed | ApartmentUnit	3,306	1,292
Sales Price	$ 1,477,275	$ 708,820
Rental Properties – Consolidated [Member]
Properties disposed | Property	11	5
Property Units disposed | ApartmentUnit	2,361	1,292
Sales Price	$ 1,080,675	$ 706,120
Rental Properties – Unconsolidated [Member]
Properties disposed | Property	2
Property Units disposed | ApartmentUnit	945
Sales Price	$ 394,500
Land Parcels [Member]
Sales Price	$ 2,100	$ 2,700