v3.26.3
Fair Value of Assets and Liabilities - Schedule of Fair Value Assumptions for Borrower Loans, Loans Held for Sale and Notes (Details)
$ in Thousands
 9 Months Ended
Sep. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower Loans, at Fair Value $ 215,711 $ 309,737
Notes, at Fair Value 212,396 243,900
Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes, at Fair Value 212,396 243,900
Level 3 Inputs    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower Loans, at Fair Value 215,711 309,737
Notes, at Fair Value 212,396 243,900
Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower Loans, at Fair Value 215,711 245,337
Notes, at Fair Value 212,396 243,900
Prosper Funding LLC | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes, at Fair Value 212,396 243,900
Prosper Funding LLC | Level 3 Inputs    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower Loans, at Fair Value 215,711 245,337
Notes, at Fair Value 212,396 243,900
Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes, at Fair Value 212,396 243,900
Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes, at Fair Value $ 212,396 243,900
Prepayment rate assumption | Applying a 1.1 multiplier to prepayment rate | Servicing Assets    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate increase 1.10%  
Prepayment rate assumption | Applying a 0.9 multiplier to prepayment rate | Servicing Assets    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate decrease 0.90%  
Discount rate assumption | 100 basis point increase in discount rate | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 210,488 241,752
Discount rate assumption | 100 basis point increase in discount rate | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes 210,488 241,752
Discount rate assumption | 200 basis point increase in discount rate | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes 208,626 239,655
Discount rate assumption | 200 basis point increase in discount rate | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes 208,626 239,655
Discount rate assumption | 100 basis point decrease in discount rate | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes 214,348 246,096
Discount rate assumption | 100 basis point decrease in discount rate | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes 214,348 246,096
Discount rate assumption | 200 basis point decrease in discount rate | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes 216,354 248,352
Discount rate assumption | 200 basis point decrease in discount rate | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 216,354 248,352
Default rate assumption | Applying a 1.1 multiplier to default rate | Servicing Assets    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate increase 1.10%  
Default rate assumption | Applying a 1.1 multiplier to default rate | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 210,644 241,944
Default rate assumption | Applying a 1.2 multiplier to default rate | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 208,892 239,987
Default rate assumption | Applying a 0.9 multiplier to default rate | Servicing Assets    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate decrease 0.90%  
Default rate assumption | Applying a 0.9 multiplier to default rate | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 214,146 245,853
Default rate assumption | Applying a 0.8 multiplier to default rate | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 215,898 247,806
Default rate assumption | 10 percent increase | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate increase 110.00%  
Default rate assumption | 10 percent increase | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 210,644 241,944
Default rate assumption | 20 percent increase | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate decrease 120.00%  
Default rate assumption | 20 percent increase | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 208,892 239,987
Default rate assumption | 10 percent decrease | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate increase 90.00%  
Default rate assumption | 10 percent decrease | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 214,146 245,853
Default rate assumption | 20 percent decrease | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate decrease 80.00%  
Default rate assumption | 20 percent decrease | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Notes $ 215,898 $ 247,806
Discount rate | 100 basis point increase in both discount rates | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Discount rates increase 100  
Discount rate | 200 basis point increase in both discount rates | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Discount rates increase 200  
Discount rate | 100 basis point decrease in both discount rates | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Discount rates increase 100  
Discount rate | 200 basis point decrease in both discount rates | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Discount rates increase 200  
Discount rate | Discount rate assumption | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Fair value assumptions 0.0934 0.0867
Discount rate | Discount rate assumption | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Fair value assumptions 0.0934 0.0867
Default rate | Applying a 1.1 multiplier to default rate | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate increase 1.10%  
Default rate | Applying a 1.1 multiplier to default rate | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate decrease 110.00%  
Default rate | Applying a 0.9 multiplier to default rate | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate decrease 0.90%  
Default rate | Applying a 0.9 multiplier to default rate | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate decrease 90.00%  
Default rate | Applying a 0.8 multiplier to default rate | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate decrease 80.00%  
Default rate | Default rate assumption | Notes | Notes    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Fair value assumptions 0.1144 0.1148
Default rate | Default rate assumption | Notes | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Fair value assumptions 0.1144 0.1148
Prepayment rate | Applying a 1.1 multiplier to prepayment rate | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate increase 1.10%  
Prepayment rate | Applying a 1.1 multiplier to prepayment rate | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate increase 110.00%  
Prepayment rate | Applying a 1.2 multiplier to default rate | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate decrease 120.00%  
Prepayment rate | Applying a 0.9 multiplier to prepayment rate | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate decrease 0.90%  
Prepayment rate | Applying a 0.9 multiplier to prepayment rate | Prosper Funding LLC | Credit Card Derivative    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate increase 90.00%  
Borrower Loans    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower Loans, at Fair Value $ 215,711 $ 309,737
Borrower Loans | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower Loans, at Fair Value 215,711 245,337
Borrower Loans | Discount rate assumption | 100 basis point increase in discount rate    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 213,776 307,014
Borrower Loans | Discount rate assumption | 100 basis point increase in discount rate | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 213,776 243,180
Borrower Loans | Discount rate assumption | 200 basis point increase in discount rate    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 211,887 304,354
Borrower Loans | Discount rate assumption | 200 basis point increase in discount rate | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 211,887 241,073
Borrower Loans | Discount rate assumption | 100 basis point decrease in discount rate    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 217,694 312,526
Borrower Loans | Discount rate assumption | 100 basis point decrease in discount rate | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 217,694 247,547
Borrower Loans | Discount rate assumption | 200 basis point decrease in discount rate    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 219,726 315,384
Borrower Loans | Discount rate assumption | 200 basis point decrease in discount rate | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 219,726 249,810
Borrower Loans | Default rate assumption | Applying a 1.1 multiplier to default rate    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 213,932 307,253
Borrower Loans | Default rate assumption | Applying a 1.2 multiplier to default rate    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 212,152 304,767
Borrower Loans | Default rate assumption | Applying a 0.9 multiplier to default rate    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans 217,489 312,219
Borrower Loans | Default rate assumption | Applying a 0.8 multiplier to default rate    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans $ 219,269 314,699
Borrower Loans | Default rate assumption | 10 percent increase    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate increase 110.00%  
Borrower Loans | Default rate assumption | 10 percent increase | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans $ 213,932 243,371
Borrower Loans | Default rate assumption | 20 percent increase    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Prepayment rate decrease 120.00%  
Borrower Loans | Default rate assumption | 20 percent increase | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans $ 212,152 241,402
Borrower Loans | Default rate assumption | 10 percent decrease    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate increase 90.00%  
Borrower Loans | Default rate assumption | 10 percent decrease | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans $ 217,489 247,304
Borrower Loans | Default rate assumption | 20 percent decrease    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Default rate decrease 80.00%  
Borrower Loans | Default rate assumption | 20 percent decrease | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Borrower loans $ 219,269 $ 249,269
Borrower Loans | Discount rate | Discount rate assumption    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Fair value assumptions 0.0934 0.0853
Borrower Loans | Discount rate | Discount rate assumption | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Fair value assumptions 0.0934 0.0867
Borrower Loans | Default rate | Default rate assumption    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Fair value assumptions 0.1144 0.1179
Borrower Loans | Default rate | Default rate assumption | Prosper Funding LLC    
Fair Value Inputs Assets Quantitative Information [Line Items]    
Fair value assumptions 0.1144 0.1148