Fair Value Measurements - Unobservable Inputs Assumptions - Securitized Debt (Details) - Loans held for investment - Level 3 - Variable Interest Entities, Primary Beneficiary	Mar. 31, 2024	Dec. 31, 2023
Discount Rate | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.06	0.06
Discount Rate | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.09	0.09
Discount Rate | Weighted Average Borrowing Rates
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.065	0.065
Prepay Rate | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.06	0.06
Prepay Rate | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.15	0.15
Prepay Rate | Weighted Average Borrowing Rates
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.074	0.079
CDR | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0	0
CDR | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.06	0.06
CDR | Weighted Average Borrowing Rates
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.008	0.008
Loss Severity | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.30	0
Loss Severity | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.55	0.55
Loss Severity | Weighted Average Borrowing Rates
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Significant Inputs	0.397	0.409