Subsequent Events - Narrative - Sale of Dawntree Apartments (Details)	Mar. 08, 2019 USD ($) apartment	Dec. 31, 2018 apartment
Subsequent Event [Line Items]
Number of units in real estate property (in number of units or apartments)		744
Subsequent Event [Member] | Dawntree Apartments [Member] | Discontinued Operations, Disposed of by Sale [Member]
Subsequent Event [Line Items]
Number of units in real estate property (in number of units or apartments)	400
Consideration | $	$ 46,200,000