Organization (Details) ft² in Millions	3 Months Ended
	Mar. 31, 2020 a ft² property market
Real Estate [Line Items]
Number of markets | market	6
Buildings
Real Estate [Line Items]
Number of properties	219
Area of real estate property | ft²	13.4
Buildings for sale
Real Estate [Line Items]
Number of properties	3
Improved land parcels
Real Estate [Line Items]
Number of properties	21
Area of real estate property | a	82.2
Redevelopment property
Real Estate [Line Items]
Number of properties	4
Area of real estate property | ft²	0.5