| Document and Entity Information | Mar. 31, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001630472 |
| Document Type | 8-K |
| Document Period End Date | Mar. 31, 2021 |
| Entity Registrant Name | TPG RE Finance Trust, Inc. |
| Entity Incorporation State Country Code | MD |
| Entity File Number | 001-38156 |
| Entity Tax Identification Number | 36-4796967 |
| Entity Address, Address Line One | 888 Seventh Avenue |
| Entity Address, Address Line Two | 35th Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10106 |
| City Area Code | (212) |
| Local Phone Number | 601-4700 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.001 per share |
| Trading Symbol | TRTX |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
