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)	Jun. 30, 2020 ft² property
Real Estate Properties [Line Items]
Number of properties | property	94
Net rentable area (in square feet) | ft²	16,585,793
Office properties
Real Estate Properties [Line Items]
Number of properties | property	83
Net rentable area (in square feet) | ft²	13,585,348
Mixed-use properties
Real Estate Properties [Line Items]
Number of properties | property	5
Net rentable area (in square feet) | ft²	780,184
Core Properties
Real Estate Properties [Line Items]
Number of properties | property	88
Net rentable area (in square feet) | ft²	14,365,532
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	3
Net rentable area (in square feet) | ft²	120,011
Held for sale properties
Real Estate Properties [Line Items]
Number of properties | property	2
Net rentable area (in square feet) | ft²	1,896,142