Quarterly report pursuant to Section 13 or 15(d)

Real Estate Facilities (Activity In Real Estate Facilities) (Details)

v3.21.1
Real Estate Facilities (Activity In Real Estate Facilities) (Details)
$ in Thousands
 3 Months Ended
Mar. 31, 2021
USD ($)
ft²
Dec. 31, 2020
ft²
Property, Plant and Equipment [Line Items]    
Beginning Balances $ 1,869,311  
Accumulated Depreciation, Beginning Balances (1,181,402)  
Capital expenditures 5,832  
Depreciation and amortization expense (22,289)  
Transfers from property held for development 9,052  
Transfer to properties held for sale 575  
Accumulated Depreciation, Ending Balances (1,199,381)  
Ending Balances $ 1,862,481  
Rentable area (in square feet) | ft² 27,800,000  
Land [Member]    
Property, Plant and Equipment [Line Items]    
Beginning Balances $ 864,092  
Transfers from property held for development 989  
Ending Balances 865,081  
Buildings And Improvements [Member]    
Property, Plant and Equipment [Line Items]    
Beginning Balances 2,186,621  
Capital expenditures 5,832  
Disposals (3,671)  
Transfers from property held for development 8,063  
Transfer to properties held for sale (64)  
Ending Balances 2,196,781  
Accumulated Depreciation [Member]    
Property, Plant and Equipment [Line Items]    
Accumulated Depreciation, Beginning Balances (1,181,402)  
Accumulated Depreciation, Disposals 3,671  
Depreciation and amortization expense (22,289)  
Transfer to properties held for sale 639  
Accumulated Depreciation, Ending Balances (1,199,381)  
Reclassification [Member] | Land [Member]    
Property, Plant and Equipment [Line Items]    
Beginning Balances (10,600)  
Reclassification [Member] | Buildings And Improvements [Member]    
Property, Plant and Equipment [Line Items]    
Beginning Balances (60,800)  
Reclassification [Member] | Accumulated Depreciation [Member]    
Property, Plant and Equipment [Line Items]    
Accumulated Depreciation, Beginning Balances $ 47,700  
Herndon, VA [Member]    
Property, Plant and Equipment [Line Items]    
Rentable area (in square feet) | ft²   244,000
Chantilly, VA [Member]    
Property, Plant and Equipment [Line Items]    
Rentable area (in square feet) | ft²   198,000