Segment Reporting (Schedule Of Selected Results Of Operations And Asset Information) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
Segment Reporting Information [Line Items]          
Total revenues $ 157,517 $ 146,158 $ 459,667 $ 448,440  
Total operating and interest expenses [1] 104,440 101,877 313,919 320,061  
Equity in earnings (loss) of unconsolidated joint ventures 21,790 3,135 19,622 (2,723)  
Net operating income (loss) [2] 74,867 47,416 165,370 125,656  
Total assets 4,435,619   4,435,619   $ 4,053,963
Total long-lived assets [3] 3,728,816   3,728,816   3,466,427
Total investments in unconsolidated joint ventures 319,807   319,807   303,457
Impairment charge   164,176   164,176  
Corporate & Other [Member]          
Segment Reporting Information [Line Items]          
Total revenues [4] (2,357) (1,125) (7,281) (3,139)  
Total operating and interest expenses [1],[4] 21,269 28,236 65,789 79,804  
Net operating income (loss) [2],[4] (23,626) (29,361) (73,070) (82,943)  
Total assets [4] 62,147   62,147   41,535
Total long-lived assets [3],[4] (4,455)   (4,455)   (1,531)
Real Estate - Commercial And Other [Member]          
Segment Reporting Information [Line Items]          
Total revenues 141,226 131,910 411,947 406,128  
Total operating and interest expenses [1] 68,533 59,810 201,914 199,178  
Equity in earnings (loss) of unconsolidated joint ventures 22,487 5,181 23,569 4,611  
Net operating income (loss) [2] 95,180 77,281 233,602 211,561  
Total assets 3,394,462   3,394,462   3,166,577
Total long-lived assets [3] 3,061,298   3,061,298   2,886,583
Total investments in unconsolidated joint ventures 80,735   80,735   76,140
Real Estate - Multi Family [Member]          
Segment Reporting Information [Line Items]          
Total revenues 8,806 6,964 27,011 20,541  
Total operating and interest expenses [1] 5,005 4,233 16,337 12,775  
Equity in earnings (loss) of unconsolidated joint ventures (1,442) (2,793) (4,773) (8,290)  
Net operating income (loss) [2] 2,359 (62) 5,901 (524)  
Total assets 963,569   963,569   836,020
Total long-lived assets [3] 667,602   667,602   577,705
Total investments in unconsolidated joint ventures 238,261   238,261   225,850
Multi Family Services [Member]          
Segment Reporting Information [Line Items]          
Total revenues 9,842 [5] 8,409 [6] 27,990 [5] 24,910 [6]  
Total operating and interest expenses [1] 9,633 [7] 9,598 [8] 29,879 [7] 28,304 [8]  
Equity in earnings (loss) of unconsolidated joint ventures 745 747 826 956  
Net operating income (loss) [2] 954 (442) (1,063) (2,438)  
Total assets 15,441   15,441   9,831
Total long-lived assets [3] 4,371   4,371   3,670
Total investments in unconsolidated joint ventures 811   811   $ 1,467
Fee revenue 3,800 1,500 10,100 5,900  
Management fee and salary reimbursement expenses $ 1,800 $ 1,000 $ 4,900 $ 4,500  
[1] Total operating and interest expenses represent the sum of: real estate taxes; utilities; operating services; direct construction costs; real estate services expenses; general and administrative, acquisition related costs and interest expense (net of interest income). All interest expense, net of interest and other investment income, (including for property-level mortgages) is excluded from segment amounts and classified in Corporate & Other for all periods.
[2] 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.
[3] Long-lived assets are comprised of net investment in rental property, unbilled rents receivable and goodwill.
[4] Corporate & Other represents all corporate-level items (including interest and other investment income, interest expense, non-property general and administrative expense, construction services revenue and direct construction costs) as well as intercompany eliminations necessary to reconcile to consolidated Company totals.
[5] Includes $3.8 million and $10.1 million of fees and salary reimbursements earned for the three and nine months ended September 30, 2016, respectively, from the multi-family real estate segment, which are eliminated in consolidation.
[6] Includes $2.2 million and $5.9 million of fees and salary reimbursements earned for the three and nine months ended September 30, 2015, respectively, from the multi-family real estate segment, which are eliminated in consolidation.
[7] Includes $1.8 million and $4.9 million of management fees and salary reimbursement expenses for the three and nine months ended September 30, 2016, respectively, from the multi-family real estate segment, which are eliminated in consolidation.
[8] Includes $1 million and $4.5 million of management fees and salary reimbursement expenses for the three and nine months ended September 30, 2016, respectively, from the multi-family real estate segment, which are eliminated in consolidation.