| Cover Page | Jul. 28, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Jul. 28, 2022 |
| Entity Registrant Name | WASHINGTON REAL ESTATE INVESTMENT TRUST |
| Entity Central Index Key | 0000104894 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 001-06622 |
| Entity Tax Identification Number | 53-0261100 |
| Entity Address, Address Line One | 1775 EYE STREET, NW |
| Entity Address, Address Line Two | SUITE 1000 |
| Entity Address, City or Town | WASHINGTON |
| Entity Address, State or Province | DC |
| Entity Address, Postal Zip Code | 20006 |
| City Area Code | 202 |
| Local Phone Number | 774-3200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Shares of Beneficial Interest |
| Trading Symbol | WRE |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
