Commitments to Acquire/Dispose of Real Estate - Separate Agreements to Acquire (Details) - Subsequent Event [Member] $ in Thousands	Feb. 16, 2018 USD ($) Property ApartmentUnit
Property/Unit schedule
Properties | Property	1
Apartment Units | ApartmentUnit	117
Purchase Price | $	$ 53,700
Rental Properties Acquired [Member]
Property/Unit schedule
Properties | Property	1
Apartment Units | ApartmentUnit	117
Purchase Price | $	$ 53,700