Investments In Unconsolidated Joint Ventures (Summary Of The Results Of Operations) (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Schedule of Equity Method Investments [Line Items]        
Total revenues $ 15,354 $ 14,130 $ 27,058 $ 24,957
Operating and other (9,080) (8,510) (16,259) (15,731)
Depreciation and amortization (2,398) (2,648) (4,788) (5,559)
Interest expense (1,652) (1,682) (3,342) (3,325)
Net income 2,224 1,290 2,669 342
Company's equity in earnings (loss) of unconsolidated joint ventures 1,733 736 2,333 635
Plaza VIII & IX Associates [Member]
        
Schedule of Equity Method Investments [Line Items]        
Total revenues 235 255 464 449
Operating and other (60) (51) (115) (102)
Depreciation and amortization (153) (153) (306) (306)
Net income 22 51 43 41
Company's equity in earnings (loss) of unconsolidated joint ventures 12 25 22 20
Harborside South Pier [Member]
        
Schedule of Equity Method Investments [Line Items]        
Total revenues 10,906 10,815 19,067 18,450
Operating and other (6,814) (6,830) (12,445) (12,564)
Depreciation and amortization (1,410) (1,415) (2,813) (2,839)
Interest expense (1,098) (1,120) (2,200) (2,245)
Net income 1,584 1,450 1,609 802
Company's equity in earnings (loss) of unconsolidated joint ventures 792 568 804 407
Red Bank Corporate Plaza [Member]
        
Schedule of Equity Method Investments [Line Items]        
Total revenues 799 865 1,646 1,592
Operating and other (182) (243) (416) (370)
Depreciation and amortization (228) (226) (456) (451)
Interest expense (186) (129) (365) (209)
Net income 203 267 409 562
Company's equity in earnings (loss) of unconsolidated joint ventures 101 134 204 281
Gramercy Agreement [Member]
        
Schedule of Equity Method Investments [Line Items]        
Total revenues 1,552 1,525 2,898 3,334
Operating and other (999) (975) (1,880) (1,892)
Depreciation and amortization (453) (539) (906) (1,332)
Interest expense (386) (381) (774) (783)
Net income (286) (370) (662) (673)
12 Vreeland [Member]
        
Schedule of Equity Method Investments [Line Items]        
Total revenues 652 594 1,246 990
Operating and other (266) (34) (288) (52)
Depreciation and amortization (154) (315) (307) (631)
Interest expense 18 (52) (3) (88)
Net income 250 193 648 219
Company's equity in earnings (loss) of unconsolidated joint ventures 125 96 324 109
Boston-Downtown Crossing [Member]
        
Schedule of Equity Method Investments [Line Items]        
Operating and other (755) (377) (1,089) (751)
Net income (755) (377) (1,089) (751)
Company's equity in earnings (loss) of unconsolidated joint ventures (227) (113) (327) (225)
Gale Jefferson [Member]
        
Schedule of Equity Method Investments [Line Items]        
Total revenues 69 76 129 142
Net income 69 76 129 142
Company's equity in earnings (loss) of unconsolidated joint ventures 20 26 40 43
Stamford SM LLC [Member]
        
Schedule of Equity Method Investments [Line Items]        
Total revenues 1,141   1,608  
Operating and other (4)   (26)  
Net income 1,137   1,582  
Company's equity in earnings (loss) of unconsolidated joint ventures $ 910   $ 1,266