Annual report pursuant to Section 13 and 15(d)

Real Estate Investments Narrative (Details)

v2.4.0.6
Real Estate Investments Narrative (Details) (USD $)
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Real Estate and Accumulated Depreciation [Line Items]      
Real estate investment property, at cost $ 2,406,783,000 $ 2,051,936,000  
Payments to Acquire Real Estate 281,701,000 [1] 155,881,000 [1] 19,828,000 [1]
Notes Assumed (78,500,000) 0 0
Credits Received At Settlement 1,300,000 500,000  
Total property purchase price 281,700,000 155,900,000 19,900,000
Land Available for Development 9,400,000    
Tenant Origination Costs Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Weighted remaining average life, in months 62    
Leasing Commissions Absorption Costs Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Weighted remaining average life, in months 51    
Net Lease Intangible Assets Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Weighted remaining average life, in months 65    
Net Lease Intangible Liabilities Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Weighted remaining average life, in months 62    
John Marshall Two And Olney Village Center Member
     
Real Estate and Accumulated Depreciation [Line Items]      
Notes Assumed 76,700,000    
Six Fifty North Glebe Road [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Payments to Acquire Businesses, Net of Cash Acquired 11,800,000    
Braddock Gateway [Member]
     
Real Estate and Accumulated Depreciation [Line Items]      
Payments to Acquire Businesses, Net of Cash Acquired $ 13,900,000    
[1] See note 3 to the consolidated financial statements for the supplemental disclosure of non-cash investing and financing activities, including the assumption of mortgage debt in conjunction with some of our real estate acquisitions.