Segment Reporting (Schedule Of Reconciliation Of Net Operating Income To Income From Continuing Operations) (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Segment Reporting Information [Line Items]    
Net operating income $ 57,696 [1] $ 69,857 [1]
Depreciation and amortization (46,504) (46,594)
Income from continuing operations 11,192 23,263
Income (loss) from discontinued operations 1,897 1,992
Realized gains (losses) and unrealized losses on disposition of rental property, net   4,012
Total discontinued operations, net 1,897 6,004
Net income 13,089 29,267
Noncontrolling interest in consolidated joint ventures 62 79
Noncontrolling interest in Operating Partnership (1,365) (2,846)
Noncontrolling interest in discontinued operations (230) (733)
Net income available to common shareholders 11,556 25,767
Operating Segments [Member]
    
Segment Reporting Information [Line Items]    
Net operating income 57,696 69,857
Net income available to common shareholders 11,556 25,767
Segment Reconciling Items [Member]
    
Segment Reporting Information [Line Items]    
Depreciation and amortization (46,504) (46,594)
Noncontrolling interest in consolidated joint ventures 62 79
Noncontrolling interest in Operating Partnership (1,365) (2,846)
Noncontrolling interest in discontinued operations $ (230) $ (733)
[1] Net operating income represents total revenues less total operating and interest expenses (as defined in Note “a”), plus equity in earnings (loss) of unconsolidated joint ventures, for the period.