Quarterly report pursuant to Section 13 or 15(d)

Discontinued Operations (Narrative) (Details)

v3.21.2
Discontinued Operations (Narrative) (Details)
$ in Thousands
1 Months Ended 3 Months Ended 9 Months Ended 33 Months Ended
Oct. 31, 2021
USD ($)
ft²
Sep. 30, 2021
USD ($)
ft²
Sep. 30, 2020
USD ($)
Sep. 30, 2021
USD ($)
ft²
item
Sep. 30, 2020
USD ($)
Sep. 30, 2021
USD ($)
ft²
property
Dec. 19, 2019
ft²
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]              
Unrealized gains (losses) on disposition of rental property   $ 500 $ 15,775 $ 569 $ (56,998)    
Proceeds from the sale of property       $ 42,702 $ 16,455    
Suburban Office Portfolio [Member]              
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]              
Area of property (in square feet) | ft²             6,600,000
Disposal Group, Not Discontinued Operations [Member]              
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]              
Number of properties sold | item       15      
Sales proceeds       $ 681,608      
Gain (loss) on sale of property       $ 25,030      
Disposal Group, Not Discontinued Operations [Member] | Suburban Office Portfolio [Member]              
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]              
Number of properties sold | property           35  
Sales proceeds           $ 1,000  
Area of property (in square feet) | ft²   6,000,000   6,000,000   6,000,000  
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Suburban Office Portfolio [Member]              
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]              
Gain (loss) on sale of property   $ 500   $ 500      
Subsequent Event [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Suburban Office Portfolio [Member]              
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]              
Area of property (in square feet) | ft² 248,480            
Proceeds from the sale of property $ 25,300