Annual report pursuant to Section 13 and 15(d)

Recent Transactions (Schedule Of Properties Acquired) (Details)

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Recent Transactions (Schedule Of Properties Acquired) (Details)
12 Months Ended
Dec. 31, 2017
USD ($)
ft²
item
Dec. 31, 2018
USD ($)
Business Acquisition [Line Items]    
Number of Buildings, Acquired | item 9  
Rentable Square Feet, Acquired | ft² 1,392,500  
Acquisition cost $ 394,589,000  
Loan balance $ 2,809,568,000 $ 2,792,651,000
Red Bank Portfolio [Member]    
Business Acquisition [Line Items]    
Number of Buildings, Acquired | item 3  
Rentable Square Feet, Acquired | ft² 279,472  
Acquisition cost $ 27,228,000  
Short Hills / Madison Portfolio [Member]    
Business Acquisition [Line Items]    
Number of Buildings, Acquired | item 6  
Rentable Square Feet, Acquired | ft² 1,113,028  
Acquisition cost $ 367,361,000  
Unsecured Revolving Credit Facility [Member] | Short Hills / Madison Portfolio [Member]    
Business Acquisition [Line Items]    
Loan balance   $ 124,500,000