v3.26.3
Fair Value of Assets and Liabilities - Schedule of Prosper's and Prosper Funding's Estimated Fair Value of Servicing Assets and Liabilities (Details) - USD ($)
$ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Servicing Assets And Liabilities Fair Value [Line Items]    
Servicing Assets $ 21,382 $ 17,402
Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Servicing Assets $ 21,382 17,601
Prepayment rate | Applying a 1.1 multiplier to prepayment rate | Credit Card Servicing Obligation Liability    
Servicing Assets And Liabilities Fair Value [Line Items]    
Prepayment rate increase 110.00%  
Prepayment rate | Applying a 1.1 multiplier to prepayment rate | Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Prepayment rate increase 1.10%  
Prepayment rate | Applying a 1.1 multiplier to prepayment rate | Prosper Funding LLC | Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Prepayment rate increase 110.00%  
Prepayment rate | Applying a 1.2 multiplier to default rate | Prosper Funding LLC | Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Prepayment rate decrease 120.00%  
Prepayment rate | Applying a 0.9 multiplier to prepayment rate | Credit Card Servicing Obligation Liability    
Servicing Assets And Liabilities Fair Value [Line Items]    
Prepayment rate decrease 90.00%  
Prepayment rate | Applying a 0.9 multiplier to prepayment rate | Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Prepayment rate decrease 0.90%  
Prepayment rate | Applying a 0.9 multiplier to prepayment rate | Prosper Funding LLC | Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Prepayment rate increase 90.00%  
Default rate | Applying a 1.1 multiplier to default rate | Credit Card Servicing Obligation Liability    
Servicing Assets And Liabilities Fair Value [Line Items]    
Default rate increase 110.00%  
Default rate | Applying a 1.1 multiplier to default rate | Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Default rate increase 1.10%  
Default rate | Applying a 1.1 multiplier to default rate | Prosper Funding LLC | Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Default rate decrease 110.00%  
Default rate | Applying a 0.9 multiplier to default rate | Credit Card Servicing Obligation Liability    
Servicing Assets And Liabilities Fair Value [Line Items]    
Default rate decrease 90.00%  
Default rate | Applying a 0.9 multiplier to default rate | Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Default rate decrease 0.90%  
Default rate | Applying a 0.9 multiplier to default rate | Prosper Funding LLC | Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Default rate decrease 90.00%  
Servicing Assets    
Servicing Assets And Liabilities Fair Value [Line Items]    
Servicing Assets $ 21,382 17,402
Servicing Assets | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Servicing Assets 21,382 17,601
Servicing Assets | Market servicing rate | Market servicing rate increase of 0.025%    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 20,161 16,398
Servicing rate increase 0.025%  
Servicing Assets | Market servicing rate | Market servicing rate increase of 0.025% | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 20,161 16,586
Servicing rate increase 0.025%  
Servicing Assets | Market servicing rate | Market servicing rate decrease of 0.025%    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 22,603 18,405
Servicing rate decrease 0.025%  
Servicing Assets | Market servicing rate | Market servicing rate decrease of 0.025% | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 22,603 18,615
Servicing rate decrease 0.025%  
Servicing Assets | Prepayment rate assumption | Applying a 1.1 multiplier to prepayment rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 20,800 16,949
Prepayment rate increase 1.10%  
Servicing Assets | Prepayment rate assumption | Applying a 1.1 multiplier to prepayment rate | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 20,800 17,143
Servicing Assets | Prepayment rate assumption | Applying a 0.9 multiplier to prepayment rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 21,978 17,863
Prepayment rate decrease 0.90%  
Servicing Assets | Prepayment rate assumption | Applying a 0.9 multiplier to prepayment rate | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 21,978 18,068
Servicing Assets | Default rate assumption | Applying a 1.1 multiplier to default rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 21,049 17,114
Default rate increase 1.10%  
Servicing Assets | Default rate assumption | Applying a 1.1 multiplier to default rate | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 21,049 17,310
Servicing Assets | Default rate assumption | Applying a 0.9 multiplier to default rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 21,715 17,689
Default rate decrease 0.90%  
Servicing Assets | Default rate assumption | Applying a 0.9 multiplier to default rate | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 21,715 $ 17,892
Servicing Assets | Market servicing rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 0.599% 0.598%
Servicing Assets | Market servicing rate | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 0.599% 0.598%
Servicing Assets | Prepayment rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 21.74% 21.65%
Servicing Assets | Prepayment rate | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 21.74% 21.72%
Servicing Assets | Default rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 11.09% 11.84%
Servicing Assets | Default rate | Prosper Funding LLC    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 11.09% 11.86%