| Document and Entity Information Document | Mar. 24, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Mar. 24, 2022 |
| Entity Registrant Name | ORION OFFICE REIT INC. |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 001-40873 |
| Entity Tax Identification Number | 87-1656425 |
| Entity Address, Address Line One | 2325 E. Camelback Road, Suite 850 |
| Entity Address, City or Town | Phoenix, |
| Entity Address, State or Province | AZ |
| Entity Address, Postal Zip Code | 85016 |
| City Area Code | (602) |
| Local Phone Number | 698-1002 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | ONL |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0001873923 |
| Amendment Flag | false |
