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)	Sep. 30, 2021 ft² property
Real Estate Properties [Line Items]
Number of Properties | property	81
Rentable area | ft²	13,651,650
Office properties
Real Estate Properties [Line Items]
Number of Properties | property	71
Rentable area | ft²	12,006,744
Mixed-use properties
Real Estate Properties [Line Items]
Number of Properties | property	5
Rentable area | ft²	942,334
Core Properties
Real Estate Properties [Line Items]
Number of Properties | property	76
Rentable area | ft²	12,949,078
Development property
Real Estate Properties [Line Items]
Number of Properties | property	1
Rentable area | ft²	205,803
Redevelopment properties
Real Estate Properties [Line Items]
Number of Properties | property	4
Rentable area | ft²	496,769