v3.26.3
Fair Value of Assets and Liabilities - Schedule of Credit Card Derivative Asset (Details)
$ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Servicing Assets And Liabilities Fair Value [Line Items]    
Credit card derivative $ 28,833 $ 48,290
Credit Card Derivative    
Servicing Assets And Liabilities Fair Value [Line Items]    
Credit card derivative 28,833 48,290
Outstanding Credit Card Principal Balance, Prosper and Coastal Allocations $ 166,457 $ 330,409
Credit Card Derivative | Discount rate on Prosper Allocations (1)    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 0.2000 0.2315
Credit Card Derivative | Discount rate on Coastal Program Fee (1)    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 0.2000 0.2315
Credit Card Derivative | Prepayment rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 0.0820 0.0822
Credit Card Derivative | Prepayment rate | Applying a 1.1 multiplier to prepayment rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 28,418 $ 47,625
Prepayment rate increase 1.10%  
Credit Card Derivative | Prepayment rate | Applying a 0.9 multiplier to prepayment rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 29,241 $ 48,964
Prepayment rate decrease 0.90%  
Credit Card Derivative | Default rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Valuation techniques 0.1392 0.1533
Credit Card Derivative | Default rate | Applying a 1.1 multiplier to default rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 24,217 $ 38,254
Default rate increase 1.10%  
Credit Card Derivative | Default rate | Applying a 0.9 multiplier to default rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 33,582 58,663
Default rate decrease 0.90%  
Credit Card Derivative | Discount rate | 100 basis point increase in both discount rates    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions $ 28,431 47,654
Credit Card Derivative | Discount rate | 200 basis point increase in both discount rates    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions 28,047 47,036
Credit Card Derivative | Discount rate | 100 basis point decrease in both discount rates    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions 29,234 48,945
Credit Card Derivative | Discount rate | 200 basis point decrease in both discount rates    
Servicing Assets And Liabilities Fair Value [Line Items]    
Expected fair value with change in assumptions 29,654 49,619
Credit Card Servicing Obligation Liability    
Servicing Assets And Liabilities Fair Value [Line Items]    
Derivative liability $ 4,728 $ 9,276
Credit Card Servicing Obligation Liability | Discount rate on Prosper Allocations (1)    
Servicing Assets And Liabilities Fair Value [Line Items]    
Derivative liability, measurement input 0.2000 0.2315
Credit Card Servicing Obligation Liability | Prepayment rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Derivative liability, measurement input 0.0820 0.0822
Credit Card Servicing Obligation Liability | Prepayment rate | Applying a 1.1 multiplier to prepayment rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Derivative liability, expected fair value with change in assumptions $ 4,673 $ 9,174
Prepayment rate increase 110.00%  
Credit Card Servicing Obligation Liability | Prepayment rate | Applying a 0.9 multiplier to prepayment rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Derivative liability, expected fair value with change in assumptions $ 4,783 $ 9,380
Prepayment rate decrease 90.00%  
Credit Card Servicing Obligation Liability | Default rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Derivative liability, measurement input 0.1392 0.1533
Credit Card Servicing Obligation Liability | Default rate | Applying a 1.1 multiplier to default rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Derivative liability, expected fair value with change in assumptions $ 4,624 $ 9,056
Default rate increase 110.00%  
Credit Card Servicing Obligation Liability | Default rate | Applying a 0.9 multiplier to default rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Derivative liability, expected fair value with change in assumptions $ 4,834 $ 9,501
Default rate decrease 90.00%  
Credit Card Servicing Obligation Liability | Market servicing rate    
Servicing Assets And Liabilities Fair Value [Line Items]    
Derivative liability, measurement input 0.0200 0.0200
Credit Card Servicing Obligation Liability | Discount rate | Market servicing rate increase of 0.10%    
Servicing Assets And Liabilities Fair Value [Line Items]    
Servicing rate increase 0.10%  
Derivative liability, expected fair value with change in assumptions $ 4,987 $ 9,761
Credit Card Servicing Obligation Liability | Discount rate | Market servicing rate decrease of 0.10%    
Servicing Assets And Liabilities Fair Value [Line Items]    
Servicing rate decrease 0.10%  
Derivative liability, expected fair value with change in assumptions $ 4,469 $ 8,792