Quarterly report pursuant to Section 13 or 15(d)

Organization And Basis Of Presentation (Details)

v3.5.0.2
Organization And Basis Of Presentation (Details)
$ in Millions
 9 Months Ended
Sep. 30, 2016
USD ($)
ft²
state
property
item
Dec. 31, 2015
USD ($)
Real Estate Properties [Line Items]    
Percentage of ownership interest 89.50% 89.50%
Number of properties owned or investment interests 263  
Aggregate square feet of the property owned or investment interest | ft² 29,000,000  
Number of states where properties are located | state 7  
Consolidated joint ventures, total real estate assets | $ $ 193.1 $ 273.4
Consolidated joint ventures, mortgages | $ 70.1 89.5
Consolidated joint ventures, other liabilities | $ $ 20.7 $ 17.5
Commercial Properties [Member]    
Real Estate Properties [Line Items]    
Number of tenants | item 1,800  
Multi-Family Properties [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 17  
Number of Apartment Units | item 5,214  
Office And Office/Flex Buildings [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 94  
Office [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 136  
Aggregate square feet of the property owned or investment interest | ft² 23,700,000  
Office Flex Buildings [Member]    
Real Estate Properties [Line Items]    
Aggregate square feet of the property owned or investment interest | ft² 4,800,000  
Flex Properties [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 110  
Unconsolidated Joint Venture Office Buildings [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 36  
Aggregate square feet of the property owned or investment interest | ft² 5,600,000  
Industrial/Warehouse Facilities [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 6  
Aggregate square feet of the property owned or investment interest | ft² 387,400  
Unconsolidated Joint Venture Multi-Family Properties [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 10  
Number of Apartment Units | item 3,587  
Parking/Retail [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 6  
Aggregate square feet of the property owned or investment interest | ft² 130,100  
Unconsolidated Joint Venture Parking/Retail Buildings [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 2  
Aggregate square feet of the property owned or investment interest | ft² 81,700  
Unconsolidated Joint Venture Hotel [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 1  
Number of Apartment Units | item 350  
Land [Member]    
Real Estate Properties [Line Items]    
Number of properties owned or investment interests 3