Segment Reporting (Schedule Of Selected Results Of Operations And Asset Information) (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Segment Reporting Information [Line Items]      
Total revenues $ 82,057 $ 90,266  
Total operating and interest expenses 71,279 74,798  
Equity in earnings (loss) of unconsolidated joint ventures (708) (681)  
Net operating income (loss) 10,070 14,787  
Total assets 5,285,532   $ 5,292,798
Total long-lived assets 4,787,921   4,763,193
Total investments in unconsolidated joint ventures 202,574   209,091
Commercial And Other Real Estate [Member]      
Segment Reporting Information [Line Items]      
Total revenues 39,549 54,077  
Total operating and interest expenses 16,290 23,992  
Equity in earnings (loss) of unconsolidated joint ventures (117) 721  
Net operating income (loss) 23,142 30,806  
Total assets 2,091,070   2,178,321
Total long-lived assets 1,890,029   1,947,053
Total investments in unconsolidated joint ventures 7,498   7,367
Multiple-Family Real Estate & Services [Member]      
Segment Reporting Information [Line Items]      
Total revenues 42,847 36,359  
Total operating and interest expenses 22,773 21,188  
Equity in earnings (loss) of unconsolidated joint ventures (591) (1,402)  
Net operating income (loss) 19,483 13,769  
Total assets 3,162,056   3,079,409
Total long-lived assets 2,894,874   2,812,306
Total investments in unconsolidated joint ventures 195,076   201,724
Corporate & Other [Member]      
Segment Reporting Information [Line Items]      
Total revenues (339) (170)  
Total operating and interest expenses 32,216 29,618  
Net operating income (loss) (32,555) $ (29,788)  
Total assets 32,406   35,068
Total long-lived assets $ 3,018   $ 3,834