Fair Value Measurement - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Line of credit receivable	$ 110,110	$ 112,742
Notes receivable and residual certificates	144,613	97,416
Payable to securitization note holders (at fair value)	25,505	46,542
Loan servicing assets (at fair value)	67,973	40,941
Loan servicing liabilities (at fair value)	7,173	4,383
Beneficial interest assets (at fair value)	613,652	396,216
Beneficial interest liabilities	20,600	5,100
Trailing fee liability (at fair value)	6,783	5,761
Fair Value, Inputs, Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Line of credit receivable	110,110	112,742
Notes receivable and residual certificates	144,613	97,416
Payable to securitization note holders (at fair value)	25,505	46,542
Loan servicing assets (at fair value)	67,973	40,941
Loan servicing liabilities (at fair value)	7,173	4,383
Beneficial interest assets (at fair value)	613,652	396,216
Beneficial interest liabilities	$ 20,550	$ 5,075