Quarterly report pursuant to Section 13 or 15(d)

Organization And Basis Of Presentation (Narrative) (Details)

v3.21.2
Organization And Basis Of Presentation (Narrative) (Details)
$ in Millions
 9 Months Ended
Sep. 30, 2021
USD ($)
ft²
property
item
state
room
Dec. 31, 2020
USD ($)
Dec. 19, 2019
ft²
Real Estate Properties [Line Items]      
Percentage of ownership interest 91.00% 90.40%  
Number of properties owned or investment interests 36    
Number of states where properties are located | state 3    
Consolidated joint ventures, total real estate assets | $ $ 479.2 $ 486.1  
Consolidated joint ventures, other assets | $ 6.1 4.5  
Consolidated joint ventures, mortgages | $ 286.1 284.8  
Consolidated joint ventures, other liabilities | $ $ 21.7 $ 21.0  
Commercial Properties [Member]      
Real Estate Properties [Line Items]      
Number of tenants | item 110    
Multi-Family Properties [Member]      
Real Estate Properties [Line Items]      
Number of properties owned or investment interests 20    
Number of units | item 6,018    
Office [Member]      
Real Estate Properties [Line Items]      
Number of properties owned or investment interests 8    
Aggregate square feet of the property owned or investment interest | ft² 5,100,000    
Unconsolidated Joint Venture Multi-Family Properties [Member]      
Real Estate Properties [Line Items]      
Number of properties owned or investment interests 6    
Number of units | item 1,786    
Unconsolidated Joint Venture Office/Flex Buildings And Hotel [Member]      
Real Estate Properties [Line Items]      
Number of properties owned or investment interests 3    
Number of units | room 723    
Parking/Retail [Member]      
Real Estate Properties [Line Items]      
Number of properties owned or investment interests 4    
Aggregate square feet of the property owned or investment interest | ft² 108,000    
Unconsolidated Joint Venture Parking/Retail Buildings [Member]      
Real Estate Properties [Line Items]      
Number of properties owned or investment interests 1    
Aggregate square feet of the property owned or investment interest | ft² 51,000    
Land [Member]      
Real Estate Properties [Line Items]      
Number of properties owned or investment interests 1    
Suburban Office Portfolio [Member]      
Real Estate Properties [Line Items]      
Area of property (in square feet) | ft²     6,600,000