Organization of The Parent Company and The Operating Partnership - Summary of Core Portfolio of Operating Properties and Excludes Development, Redevelopment and Held for Sale (Details)	Mar. 31, 2020 ft² property
Real Estate Properties [Line Items]
Number of properties | property	94
Net rentable area (in square feet) | ft²	16,580,310
Office properties
Real Estate Properties [Line Items]
Number of properties | property	85
Net rentable area (in square feet) | ft²	15,319,340
Mixed-use properties
Real Estate Properties [Line Items]
Number of properties | property	4
Net rentable area (in square feet) | ft²	659,625
Core Properties
Real Estate Properties [Line Items]
Number of properties | property	89
Net rentable area (in square feet) | ft²	15,978,965
Development property
Real Estate Properties [Line Items]
Number of properties | property	1
Net rentable area (in square feet) | ft²	204,108
Redevelopment properties
Real Estate Properties [Line Items]
Number of properties | property	4
Net rentable area (in square feet) | ft²	397,237