| Document and Entity Information Document | Feb. 02, 2021 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 2, 2021 |
| Entity Registrant Name | BRANDYWINE REALTY TRUST |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 001-9106 |
| Entity Tax Identification Number | 23-2413352 |
| Entity Address, Address Line One | 2929 Walnut Street |
| Entity Address, Address Line Two | Suite 1700 |
| Entity Address, City or Town | Philadelphia |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 19104 |
| City Area Code | 610 |
| Local Phone Number | 325-5600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Shares of Beneficial Interest |
| Trading Symbol | BDN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000790816 |
| Amendment Flag | false |
| Brandywine Operating Partnership, L.P. [Member] | |
| Entity Information [Line Items] | |
| Entity Registrant Name | BRANDYWINE OPERATING PARTNERSHIP, L.P. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 000-24407 |
| Entity Tax Identification Number | 23-2862640 |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001060386 |
