| Cover Page | Feb. 16, 2022 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 16, 2022 |
| Entity Registrant Name | OFFICE PROPERTIES INCOME TRUST |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 001-34364 |
| Entity Tax Identification Number | 26-4273474 |
| Entity Address, Address Line One | Two Newton Place, |
| Entity Address, Address Line Two | 255 Washington Street, |
| Entity Address, Address Line Three | Suite 300, |
| Entity Address, City or Town | Newton, |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02458-1634 |
| City Area Code | 617 |
| Local Phone Number | 219-1440 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001456772 |
| Amendment Flag | false |
| Common Shares Of Beneficial Interest | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Shares of Beneficial Interest |
| Trading Symbol | OPI |
| Security Exchange Name | NASDAQ |
| 6.375% Senior Notes due 2050 | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 6.375% Senior Notes due 2050 |
| Trading Symbol | OPINL |
| Security Exchange Name | NASDAQ |
