Quarterly report pursuant to Section 13 or 15(d)

Mortgages, Loans Payable And Other Obligations (Narrative) (Details)

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Mortgages, Loans Payable And Other Obligations (Narrative) (Details)
 6 Months Ended
Jun. 30, 2018
USD ($)
property
Jun. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Debt Instrument [Line Items]      
Number of properties with encumbered company mortgages | property 14    
Carrying value of encumbered properties $ 1,700,000,000    
Cash paid for interest 41,354,000 $ 49,652,000  
Interest capitalized 14,296,000 9,173,000  
Total indebtedness $ 2,660,517,000   $ 2,826,110,000
Total indebtedness, weighted average interest rate 3.79%   3.93%
Projects Under Development And Developable Land [Member]      
Debt Instrument [Line Items]      
Number of properties with encumbered company mortgages | property 2    
Other Property [Member]      
Debt Instrument [Line Items]      
Carrying value of encumbered properties $ 249,000,000    
Unconsolidated Joint Venture [Member]      
Debt Instrument [Line Items]      
Interest capitalized 348,000 $ 1,009,000  
Revolving Credit Facility Borrowing And Other Variable Rate Mortgage Debt [Member]      
Debt Instrument [Line Items]      
Total indebtedness $ 494,490,000   $ 382,443,000
Total indebtedness, weighted average interest rate 4.33%   3.63%
Fixed Rate Debt And Other Obligations [Member]      
Debt Instrument [Line Items]      
Total indebtedness $ 2,166,027,000   $ 2,443,667,000
Total indebtedness, weighted average interest rate 3.66%   3.98%