v3.26.3
Related Party Transactions and Arrangements - Narrative (Details)
$ in Thousands
3 Months Ended 9 Months Ended
Aug. 10, 2026
USD ($)
Mar. 18, 2026
USD ($)
Sep. 30, 2026
USD ($)
position
Mar. 31, 2026
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2026
USD ($)
position
Sep. 30, 2025
USD ($)
Apr. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
property
Nov. 30, 2022
property
Jun. 30, 2022
USD ($)
property
Sep. 30, 2021
USD ($)
Sep. 17, 2021
USD ($)
Related Party Transaction [Line Items]                          
Equity method investments     $ 88,656     $ 88,656     $ 71,682        
Total commercial mortgage loans, held for investment, net [1]     3,967,590     3,967,590     4,383,134        
Interest income     $ 84,218   $ 106,167 $ 273,654 $ 331,246            
Number of positions with net unrealized gain (loss) period less than 12 months | position     13     13              
Amortized cost basis     $ 187,900     $ 187,900              
Unrealized (Loss)     900     900              
BSP TMO Master JV LLC                          
Related Party Transaction [Line Items]                          
Equity method investment, ownership percentage 95.00%                        
Commercial Mortgage Receivable, Held-For-Investment                          
Related Party Transaction [Line Items]                          
Total commercial mortgage loans, held for investment, net     3,967,590     3,967,590     4,383,134        
Commercial Mortgage Receivable, Held-For-Investment | Commercial Portfolio Segment                          
Related Party Transaction [Line Items]                          
Total commercial mortgage loans, held for investment, net     3,967,590     3,967,590     $ 4,383,134        
Industrial | Jeffersonville, GA | Mortgages                          
Related Party Transaction [Line Items]                          
Principal amount                         $ 113,600
Industrial | Jeffersonville, GA | Franklin BSP Realty Trust, Inc | Mortgages | September 2021 Mortgage Note Payable, Eliminated in Consolidation                          
Related Party Transaction [Line Items]                          
Principal amount                         $ 89,400
Industrial | Jeffersonville, GA | Jeffersonville JV, Affiliate                          
Related Party Transaction [Line Items]                          
Equity method investments                       $ 5,800  
Noncontrolling interest in joint ventures                       29,800  
Retail | Various | Walgreens JV                          
Related Party Transaction [Line Items]                          
Number of real estate properties | property                 1 24      
Affiliated Entity | Gardena JV                          
Related Party Transaction [Line Items]                          
Equity method investment, ownership percentage   62.05%                      
Nonrelated Party | Gardena JV                          
Related Party Transaction [Line Items]                          
Equity method investment, ownership percentage   10.00%                      
Related Party | Gardena JV                          
Related Party Transaction [Line Items]                          
Payments to acquire property   $ 44,000                      
Equity method investment, ownership percentage   27.95%                      
Related Party | BSP TMO Master JV LLC                          
Related Party Transaction [Line Items]                          
Payments to acquire property $ 1,900                        
Equity method investment, ownership percentage 95.00%                        
Related Party | Commercial Mortgage Receivable, Held-For-Investment                          
Related Party Transaction [Line Items]                          
Total commercial mortgage loans, held for investment, net     37,100     37,100     $ 37,100        
Interest income     700   $ 700 2,000 $ 2,000            
Related Party | Industrial | Jeffersonville, GA                          
Related Party Transaction [Line Items]                          
Real estate investment property, net                       $ 139,500  
Related Party | Industrial | Jeffersonville, GA | Franklin BSP Realty Trust, Inc                          
Related Party Transaction [Line Items]                          
Noncontrolling interest, ownership percentage by parent                       79.00%  
Real estate investments, joint ventures                       $ 109,800  
Equity method investments                       21,100  
Related Party | Industrial | Jeffersonville, GA | Franklin BSP Realty Trust, Inc | Mortgages | September 2021 Mortgage Note Payable, Eliminated in Consolidation                          
Related Party Transaction [Line Items]                          
Principal amount               $ 89,400       $ 88,700  
Fund               $ 24,200          
Related Party | Industrial | Jeffersonville, GA | Jeffersonville JV, Affiliate                          
Related Party Transaction [Line Items]                          
Noncontrolling interest, ownership percentage by noncontrolling owners                       21.00%  
Related Party | Industrial | Jeffersonville, GA | Jeffersonville JV, Affiliate | Mortgages | September 2021 Mortgage Note Payable, Affiliate                          
Related Party Transaction [Line Items]                          
Principal amount                       $ 24,000  
Related Party | Retail | Various | Walgreens JV                          
Related Party Transaction [Line Items]                          
Number of real estate properties | property                     24    
Related Party | Retail | Various | Franklin BSP Realty Trust, Inc | Walgreens JV                          
Related Party Transaction [Line Items]                          
Noncontrolling interest, ownership percentage by parent                     75.618%    
Related Party | Retail | Various | Walgreens JV, Affiliate | Walgreens JV                          
Related Party Transaction [Line Items]                          
Noncontrolling interest, ownership percentage by noncontrolling owners                     24.242%    
Related Party | Retail | Various | Walgreens JV, Affiliate | Commercial Portfolio Segment                          
Related Party Transaction [Line Items]                          
Total commercial mortgage loans, held for investment, net                     $ 149,700    
Affiliated Entity                          
Related Party Transaction [Line Items]                          
Servicing fee income     $ 1,400     $ 3,400              
Aggregate principal balance       $ 124,700                  
Accrued interest       400                  
Debt assumption on repurchases agreements       $ 99,600                  
Nonrelated Party | BSP TMO Master JV LLC                          
Related Party Transaction [Line Items]                          
Equity method investment, ownership percentage 5.00%                        
Benefit Street Partners LLC | Related Party                          
Related Party Transaction [Line Items]                          
Monthly asset management fee (percent)     0.125%     0.125%              
Subordinated performance fee, percent that total return exceeds per year     6.00%     6.00%              
Percent of excess total return     15.00%     15.00%              
Maximum annual subordinated performance fee payable percent of total return     10.00%     10.00%              
Benefit Street Partners LLC | Related Party | Fee to Acquire and Originate Real Estate Debt                          
Related Party Transaction [Line Items]                          
Transaction rate (percent)           0.50%              
[1] Includes pledged assets of $364.1 million and $329.2 million as of September 30, 2026 and December 31, 2025, respectively.