Business Combinations - Schedule of Proforma Financial Information (Details) $ in Thousands	3 Months Ended
Mar. 31, 2025 USD ($)
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]
Revenue	$ 74,985
Net income (loss) attributable to Franklin BSP Realty Trust, Inc.	$ 29,420

Amount, after tax, of pro forma income (loss) of combined entity as if acquisition date of business combination occurred as of beginning of period.

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