Mortgages, Loans Payable And Other Obligations (Narrative) (Details) (USD $)
3 Months Ended
Mar. 31, 2015
property
Mar. 31, 2014
Dec. 31, 2014
Debt Instrument [Line Items]      
Number of properties with encumbered company mortgages 28    
Book value of encumbered properties $ 968,000,000    
Cash paid for interest 25,922,000 36,119,000  
Interest capitalized 3,607,000 3,141,000  
Total indebtedness 2,107,572,000   2,088,654,000
Total indebtedness, weighted average interest rate 5.65%   5.64%
Revolving Credit Facility Borrowing And Other Variable Rate Mortgage Debt [Member]      
Debt Instrument [Line Items]      
Total indebtedness 179,795,000   159,860,000
Total indebtedness, weighted average interest rate 3.33%   3.83%
Fixed Rate Debt And Other Obligations [Member]      
Debt Instrument [Line Items]      
Total indebtedness 1,927,777,000   1,928,794,000
Total indebtedness, weighted average interest rate 5.87%   5.79%
Unconsolidated Joint Venture [Member]      
Debt Instrument [Line Items]      
Interest capitalized $ 1,256,000 $ 918,000