Segment Reporting (Schedule Of Selected Results Of Operations And Asset Information) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Segment Reporting Information [Line Items]          
Total revenues $ 130,461 $ 126,589 $ 264,710 $ 265,556  
Total operating and interest expenses 94,162 84,633 188,203 181,084  
Equity in earnings (loss) of unconsolidated joint ventures (88) (52) (769) 1,520  
Net operating income (loss) 36,211 41,904 75,738 85,992  
Total assets 5,327,712   5,327,712   $ 5,060,644
Total long-lived assets 4,768,032   4,768,032   4,420,679
Total investments in unconsolidated joint ventures 215,957   215,957   232,750
Commercial And Other Real Estate [Member]          
Segment Reporting Information [Line Items]          
Total revenues 85,372 101,792 183,432 216,978  
Total operating and interest expenses 35,435 43,116 77,377 97,097  
Equity in earnings (loss) of unconsolidated joint ventures 512 909 1,233 769  
Net operating income (loss) 50,449 59,585 107,288 120,650  
Total assets 2,369,831   2,369,831   2,687,178
Total long-lived assets 2,133,587   2,133,587   2,413,696
Total investments in unconsolidated joint ventures 10,646   10,646   13,699
Multiple-Family Real Estate & Services [Member]          
Segment Reporting Information [Line Items]          
Total revenues 44,708 24,781 81,067 48,640  
Total operating and interest expenses 22,429 16,194 43,618 32,291  
Equity in earnings (loss) of unconsolidated joint ventures (600) (961) (2,002) 751  
Net operating income (loss) 21,679 7,626 35,447 17,100  
Total assets 2,898,154   2,898,154   2,260,497
Total long-lived assets 2,600,683   2,600,683   1,973,826
Total investments in unconsolidated joint ventures 204,921   204,921   218,771
Corporate & Other [Member]          
Segment Reporting Information [Line Items]          
Total revenues 381 16 211 (62)  
Total operating and interest expenses 36,298 25,323 67,208 51,696  
Net operating income (loss) (35,917) $ (25,307) (66,997) $ (51,758)  
Total assets 59,727   59,727   112,969
Total long-lived assets 33,762   33,762   33,157
Total investments in unconsolidated joint ventures $ 390   $ 390   $ 280