Annual report pursuant to Section 13 and 15(d)

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

v3.8.0.1
Mortgages, Loans Payable And Other Obligations (Narrative) (Details)
 12 Months Ended
Dec. 31, 2017
USD ($)
property
item
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Debt Instrument [Line Items]      
Cash paid for interest $ 103,559,000 $ 122,414,000 $ 115,123,000
Interest capitalized 20,240,000 19,316,000 16,217,000
Total indebtedness 2,809,568,000    
Adjusted total indebtedness $ 2,826,110,000 $ 2,357,055,000  
Total indebtedness, weighted average interest rate 3.93% 3.79%  
Projects Under Development And Developable Land [Member]      
Debt Instrument [Line Items]      
Number of projects with encumbered company mortgages | item 5    
Carrying value of encumbered properties $ 435,000,000    
Other Property [Member]      
Debt Instrument [Line Items]      
Number of properties with encumbered company mortgages | property 15    
Carrying value of encumbered properties $ 1,600,000,000    
Unconsolidated Joint Venture [Member]      
Debt Instrument [Line Items]      
Interest capitalized 1,056,000 $ 5,055,000 $ 5,325,000
Revolving Credit Facility Borrowing And Other Variable Rate Mortgage Debt [Member]      
Debt Instrument [Line Items]      
Total indebtedness $ 382,443,000 $ 481,282,000  
Total indebtedness, weighted average interest rate 3.63% 2.93%  
Fixed Rate Debt And Other Obligations [Member]      
Debt Instrument [Line Items]      
Total indebtedness $ 2,443,667,000 $ 1,875,773,000  
Total indebtedness, weighted average interest rate 3.98% 4.01%