| Document and Entity Information Document | Aug. 29, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Aug. 29, 2022 |
| Entity Registrant Name | Griffin Realty Trust, Inc. |
| Entity Central Index Key | 0001600626 |
| Amendment Flag | false |
| Entity File Number | 000-55605 |
| Entity Incorporation, State or Country Code | MD |
| Entity Tax Identification Number | 46-4654479 |
| Entity Address, Address Line One | 1520 E. Grand Avenue |
| Entity Address, City or Town | El Segundo |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90245 |
| City Area Code | 310 |
| Local Phone Number | 606-3200 |
| Written Communications | false |
| Soliciting Material | true |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
