v3.25.4
FAIR VALUE MEASUREMENTS - Significant Valuation Inputs (Details)
$ in Thousands
Sep. 30, 2025
USD ($)
Dec. 31, 2024
USD ($)
Sep. 30, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, Fair Value $ 239,694 $ 163,489   $ 37,066  
Loan, Held-for-Sale, Fair Value 389,032 395,922 $ 468,142 255,516 $ 245,890
Residual interest securities          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, Fair Value 38,308 34,506   11,952  
Level 3          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, Fair Value 100,000 88,497   55,860  
Loan, Held-for-Sale, Fair Value $ 389,032 $ 369,983   $ 255,516  
Level 3 | Discount Rate          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.129 0.129   0.129  
Loans Held For Sale, measurement input 0.055 0.076   0.105  
Level 3 | Discount Rate | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.077  
Level 3 | Discount Rate | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.109  
Level 3 | CPR          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.135 0.142   0.142  
Loans Held For Sale, measurement input 0.131 0.137   0.163  
Level 3 | CPR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.003  
Level 3 | CPR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.190  
Level 3 | CPR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.140  
Level 3 | CDR          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.007 0.007   0.011  
Loans Held For Sale, measurement input 0.014 0.017   0.016  
Level 3 | CDR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.002  
Level 3 | CDR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.637  
Level 3 | CDR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.016  
Level 3 | Servicing Rate          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.003 0.002   0.001  
Loans Held For Sale, measurement input   0      
Level 3 | Loss Severity          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input       0.502  
Level 3 | Loss Severity | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.376  
Level 3 | Loss Severity | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.600  
Level 3 | Loss Severity | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held for Investment measurement input       0.670  
Level 3 | Residual interest securities          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, Fair Value $ 38,308 $ 34,506   $ 11,952  
Level 3 | Residual interest securities | Discount Rate | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, measurement input 0.115 0.145   0.210  
Level 3 | Residual interest securities | Discount Rate | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, measurement input 0.246 0.240   0.213  
Level 3 | Residual interest securities | Discount Rate | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, measurement input 0.183 0.197   0.212  
Level 3 | Residual interest securities | CPR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, measurement input 0.162 0.152   0.136  
Level 3 | Residual interest securities | CPR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, measurement input 0.208 0.201   0.300  
Level 3 | Residual interest securities | CPR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, measurement input 0.188 0.177   0.167  
Level 3 | Residual interest securities | CDR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, measurement input 0 0.015   0.005  
Level 3 | Residual interest securities | CDR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, measurement input 0.024 0.017   0.489  
Level 3 | Residual interest securities | CDR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Marketable Securities, measurement input 0.012 0.016   0.013  
Level 3 | HELOC loans          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, Fair Value $ 98,120 $ 86,465   $ 53,645  
Loan, Held-for-Sale, Fair Value $ 323,184 $ 366,154   244,670  
Loan, Held-for-Investment, Fair Value       $ 61,337  
Level 3 | HELOC loans | Discount Rate | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.130 0.130   0.120  
Loans Held For Sale, measurement input 0.049 0.064   0.076  
Level 3 | HELOC loans | Discount Rate | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.130 0.130   0.140  
Loans Held For Sale, measurement input 0.089 0.101   0.177  
Loans Held for Investment measurement input       0.195  
Level 3 | HELOC loans | Discount Rate | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.130 0.130   0.130  
Loans Held For Sale, measurement input 0.065 0.076   0.106  
Level 3 | HELOC loans | CPR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0 0.010   0.100  
Loans Held For Sale, measurement input 0.026 0.013   0.004  
Level 3 | HELOC loans | CPR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.325 0.330   0.194  
Loans Held For Sale, measurement input 0.396 0.324   0.210  
Level 3 | HELOC loans | CPR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.137 0.144   0.146  
Loans Held For Sale, measurement input 0.156 0.136   0.160  
Level 3 | HELOC loans | CDR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0 0   0.003  
Loans Held For Sale, measurement input 0 0.015   0.005  
Level 3 | HELOC loans | CDR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.049 0.044   0.023  
Loans Held For Sale, measurement input 0.943 0.017   0.489  
Level 3 | HELOC loans | CDR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.008 0.007   0.011  
Loans Held For Sale, measurement input 0.016 0.016   0.013  
Level 3 | HELOC loans | Servicing Rate          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.003 0.002   0.001  
Level 3 | HELOC loans | Loss Severity | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0 0.166   0.396  
Level 3 | HELOC loans | Loss Severity | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.976 0.442   0.581  
Level 3 | HELOC loans | Loss Severity | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.284 0.324   0.484  
Level 3 | Mortgage loans          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, Fair Value $ 1,880 $ 2,032   $ 2,215  
Level 3 | Mortgage loans | Discount Rate | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.095 0.100   0.090  
Level 3 | Mortgage loans | Discount Rate | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.105 0.110   0.110  
Level 3 | Mortgage loans | Discount Rate | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.103 0.108   0.100  
Level 3 | Mortgage loans | CPR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.036 0.039   0.042  
Level 3 | Mortgage loans | CPR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.080 0.082   0.074  
Level 3 | Mortgage loans | CPR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.053 0.057   0.050  
Level 3 | Mortgage loans | CDR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0 0   0.001  
Level 3 | Mortgage loans | CDR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.011 0.010   0.005  
Level 3 | Mortgage loans | CDR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0.004 0.002   0.002  
Level 3 | Mortgage loans | Servicing Rate          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Servicing Assets, measurement Input 0 0      
Level 3 | Other          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loan, Held-for-Sale, Fair Value $ 2,913 $ 3,829   $ 10,846  
Level 3 | Other | Discount Rate | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.062 0.051   0.065  
Level 3 | Other | Discount Rate | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.087 0.087   0.101  
Level 3 | Other | Discount Rate | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.071 0.069   0.082  
Level 3 | Other | CPR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.180 0.179   0.138  
Level 3 | Other | CPR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.404 0.997   0.456  
Level 3 | Other | CPR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.247 0.256   0.235  
Level 3 | Other | CDR | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.013 0.004   0.014  
Level 3 | Other | CDR | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.087 0.102   0.112  
Level 3 | Other | CDR | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.061 0.077   0.074  
Level 3 | Other | Loss Severity | Minimum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.880 0.880   0.880  
Level 3 | Other | Loss Severity | Maximum          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.920 0.920   0.920  
Level 3 | Other | Loss Severity | Weighted average          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Loans Held For Sale, measurement input 0.900 0.900   0.900