| Document and Entity Information | May 04, 2020 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | May 4, 2020 |
| Entity File Number | 001-34436 |
| Entity Registrant Name | Starwood Property Trust, Inc. |
| Entity Incorporation, State or Country Code | MD |
| Entity Tax Identification Number | 27-0247747 |
| Entity Address, Address Line One | 591 West Putnam Avenue |
| Entity Address, State or Province | CT |
| Entity Address, City or Town | Greenwich |
| Entity Address, Postal Zip Code | 06830 |
| City Area Code | 203 |
| Local Phone Number | 422-7700 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $0.01 par value per share |
| Trading Symbol | STWD |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001465128 |
| Amendment Flag | false |
