ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP - Narrative (Details)	6 Months Ended
	Jun. 30, 2025 a ft² property parcel
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of real estate properties | property	63
Area of real estate property (in square feet)	11,755,704
Unconsolidated Properties | Unconsolidated Real Estate Ventures
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of real estate properties | property	9
Parent Company
Organization of The Parent Company and The Operating Partnership [Line Items]
Area of real estate property (in square feet)	11,900,000
Areas of land held for development (in acres) | a	129.5
Lease agreement term	99 years
Area of additional undeveloped parcels of land with option to purchase (in acres) | a	5.1
Parent Company | Parcel of land
Organization of The Parent Company and The Operating Partnership [Line Items]
Lease agreement term	99 years
Parent Company | Leashold Interest Land
Organization of The Parent Company and The Operating Partnership [Line Items]
Areas of land held for development (in acres) | a	0.8
Number of parcels of land | parcel	1
Wholly-owned Management Company Subsidiaries
Organization of The Parent Company and The Operating Partnership [Line Items]
Area of real estate property (in square feet)	19,000,000.0
Wholly-owned Management Company Subsidiaries | Wholly Owned Properties
Organization of The Parent Company and The Operating Partnership [Line Items]
Area of real estate property (in square feet)	11,800,000
Wholly-owned Management Company Subsidiaries | Partially Owned Properties
Organization of The Parent Company and The Operating Partnership [Line Items]
Area of real estate property (in square feet)	7,200,000
Brandywine Operating Partnership LP
Organization of The Parent Company and The Operating Partnership [Line Items]
Ownership in the operating partnership	99.70%