| Cover | Oct. 19, 2021 |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Amendment Description | On October 21, 2021, Franklin BSP Realty Trust, Inc. (“FBRT”) filed a Current Report on Form 8-K with the U.S. Securities and Exchange Commission (the “SEC”) in connection with the consummation on October 19, 2021 (the “Closing Date”), of the transactions contemplated by that certain Agreement and Plan of Merger, dated as of July 25, 2021, as amended pursuant to that certain First Amendment to Agreement and Plan of Merger, dated as of September 22, 2021 (as amended, the “Merger Agreement”), by and among FBRT, Rodeo Sub I, LLC (“Merger Sub”), Capstead Mortgage Corporation (“Capstead”) and, solely for the purposes set forth therein, Benefit Street Partners L.L.C., FBRT’s external manager (“BSP”). Pursuant to the Merger Agreement, on the Closing Date, Capstead merged with and into Merger Sub, with Merger Sub continuing as the surviving company (the “Merger”). This Current Report on Form 8-K/A is being filed to amend the Form 8-K to provide the financial statements and pro forma financial information described below, in accordance with the requirements of Item 9.01 of Form 8-K. |
| Document Period End Date | Oct. 19, 2021 |
| Entity File Number | 000-55188 |
| Entity Registrant Name | Franklin BSP Realty Trust, Inc. |
| Entity Central Index Key | 0001562528 |
| Entity Tax Identification Number | 46-1406086 |
| Entity Incorporation, State or Country Code | MD |
| Entity Address, Address Line One | 1345 Avenue of the Americas |
| Entity Address, Address Line Two | Suite 32A |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10105 |
| City Area Code | 212 |
| Local Phone Number | 588-6770 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock [Member] | |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | FBRT |
| Security Exchange Name | NYSE |
| Series E Preferred Stock [Member] | |
| Title of 12(b) Security | 7.50% Series E Cumulative Redeemable Preferred Stock, par value $0.01 per share |
| Trading Symbol | FBRT PRE |
| Security Exchange Name | NYSE |
