Recent Transactions (Schedule Of Purchase Price Allocation) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Business Acquisition [Line Items]    
Land and leasehold interest $ 38,250  
Buildings and improvements and other assets 311,346  
Above market leases [1] 6,485  
In-place lease values [1] 48,775  
Sub Total 404,856  
Less: Below market lease values [1] (10,267)  
Net assets recorded upon acquisition $ 394,589  
Above Market, In-Place And Below Market Leases [Member]    
Business Acquisition [Line Items]    
Amortization period 5 years 4 months 24 days 8 years 1 month 6 days
11 Martine Avenue [Member]    
Business Acquisition [Line Items]    
Land and leasehold interest   $ 2,460
Buildings and improvements and other assets   8,290
Net assets recorded upon acquisition   10,750
320, 321 University Avenue [Member]    
Business Acquisition [Line Items]    
Land and leasehold interest   7,305
Buildings and improvements and other assets   15,695
Net assets recorded upon acquisition   23,000
101 Wood Avenue South [Member]    
Business Acquisition [Line Items]    
Land and leasehold interest   8,509
Buildings and improvements and other assets   72,738
Above market leases [2]   58
In-place lease values [2]   6,743
Sub Total   88,048
Less: Below market lease values [2]   (5,748)
Net assets recorded upon acquisition   82,300
111 River Street [Member]    
Business Acquisition [Line Items]    
Land and leasehold interest   204
Buildings and improvements and other assets   198,609
Above market leases [2]   617
In-place lease values [2]   43,801
Other assets   11,279
Sub Total   254,510
Less: Below market lease values [2]   (43,749)
Net assets recorded upon acquisition   $ 210,761
Red Bank Portfolio [Member]    
Business Acquisition [Line Items]    
Land and leasehold interest $ 7,914  
Buildings and improvements and other assets 16,047  
Above market leases [1] 118  
In-place lease values [1] 3,171  
Sub Total 27,250  
Less: Below market lease values [1] (22)  
Net assets recorded upon acquisition 27,228  
Short Hills / Madison Portfolio [Member]    
Business Acquisition [Line Items]    
Land and leasehold interest 30,336  
Buildings and improvements and other assets 295,299  
Above market leases [1] 6,367  
In-place lease values [1] 45,604  
Sub Total 377,606  
Less: Below market lease values [1] (10,245)  
Net assets recorded upon acquisition $ 367,361  
[1] Above market, in-place and below market leases are being amortized over a weighted-average term of 5.4 years.
[2] Above market, in-place and below market leases are being amortized over a weighted-average term of 8.1 years