v3.26.3
Fair Value of Financial Instruments - Schedule of Quantitative Information Regarding Significant and Unobservable Inputs Used in the Valuation of Level 3 Assets and Liabilities Measured at Fair Value (Details)
$ in Thousands
Sep. 30, 2026
USD ($)
month
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Sep. 30, 2025
USD ($)
Jun. 30, 2025
USD ($)
Dec. 31, 2024
USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Equity investments $ 17,926   $ 24,711      
Mortgage servicing rights 18,970 $ 19,093 20,893 $ 21,896 $ 19,449 $ 21,003
Equity investments            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Equity investments 17,926   24,711      
Level 3            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, at fair value 4,939,908          
Equity investments 17,926   24,711      
Mortgage servicing rights 18,970   20,893      
Level 3 | Equity investments            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Equity investments 17,926          
Level 3 | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Mortgage servicing rights 18,970          
Level 3 | IRLCs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair Value $ 279          
Level 3 | Default rate | Valuation Technique, Discounted Cash Flow | Weighted Average | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Servicing asset, measurement input 0.026          
Level 3 | Default rate | Valuation Technique, Discounted Cash Flow | Minimum | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Servicing asset, measurement input 0          
Level 3 | Default rate | Valuation Technique, Discounted Cash Flow | Maximum | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Servicing asset, measurement input 0.417          
Level 3 | Yield | Valuation Technique, Discounted Cash Flow | Weighted Average | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Servicing asset, measurement input 0.122          
Level 3 | Yield | Valuation Technique, Discounted Cash Flow | Minimum | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Servicing asset, measurement input 0.105          
Level 3 | Yield | Valuation Technique, Discounted Cash Flow | Maximum | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Servicing asset, measurement input 0.155          
Level 3 | Discount rate | Valuation Technique, Discounted Cash Flow | Weighted Average | Equity investments            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Equity method investment, measurement input 0.155          
Level 3 | Discount rate | Valuation Technique, Discounted Cash Flow | Minimum | Equity investments            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Equity method investment, measurement input 0.150          
Level 3 | Discount rate | Valuation Technique, Discounted Cash Flow | Maximum | Equity investments            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Equity method investment, measurement input 0.165          
Level 3 | Months to assumed redemption | Valuation Technique, Discounted Cash Flow | Weighted Average | Equity investments            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Equity method investment, measurement input | month 16.6          
Level 3 | Months to assumed redemption | Valuation Technique, Discounted Cash Flow | Minimum | Equity investments            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Equity method investment, measurement input | month 3.1          
Level 3 | Months to assumed redemption | Valuation Technique, Discounted Cash Flow | Maximum | Equity investments            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Equity method investment, measurement input | month 23          
Level 3 | Lifetime voluntary prepayment rate | Valuation Technique, Discounted Cash Flow | Weighted Average | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Servicing asset, measurement input 0.072          
Level 3 | Lifetime voluntary prepayment rate | Valuation Technique, Discounted Cash Flow | Minimum | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Servicing asset, measurement input 0          
Level 3 | Lifetime voluntary prepayment rate | Valuation Technique, Discounted Cash Flow | Maximum | MSRs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Servicing asset, measurement input 0.280          
Level 3 | Pull-through rate | Valuation Technique, Probability-Weighted Expected Cash Flow | Weighted Average | IRLCs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative asset, measurement Input 0.800          
Level 3 | Pull-through rate | Valuation Technique, Probability-Weighted Expected Cash Flow | Minimum | IRLCs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative asset, measurement Input 0.795          
Level 3 | Pull-through rate | Valuation Technique, Probability-Weighted Expected Cash Flow | Maximum | IRLCs            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative asset, measurement Input 0.819          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Valuation Technique, Discounted Cash Flow            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, at fair value $ 3,573,782          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Valuation Technique, Liquidation Model            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, at fair value 115,895          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Valuation Technique, Transaction Price            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, at fair value $ 202,673          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Lifetime CPR | Valuation Technique, Discounted Cash Flow | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.100          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Lifetime CPR | Valuation Technique, Discounted Cash Flow | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Lifetime CPR | Valuation Technique, Discounted Cash Flow | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.462          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Default rate | Valuation Technique, Discounted Cash Flow | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.007          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Default rate | Valuation Technique, Discounted Cash Flow | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Default rate | Valuation Technique, Discounted Cash Flow | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 1.000          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Loss severity | Valuation Technique, Discounted Cash Flow | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.112          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Loss severity | Valuation Technique, Discounted Cash Flow | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Loss severity | Valuation Technique, Discounted Cash Flow | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 1.000          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Yield | Valuation Technique, Discounted Cash Flow | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.073          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Yield | Valuation Technique, Discounted Cash Flow | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.057          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Yield | Valuation Technique, Discounted Cash Flow | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.434          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Yield | Valuation Technique, Liquidation Model | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.083          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Yield | Valuation Technique, Liquidation Model | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.075          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Yield | Valuation Technique, Liquidation Model | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.827          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Annual home price appreciation/(depreciation) | Valuation Technique, Liquidation Model | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.019          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Annual home price appreciation/(depreciation) | Valuation Technique, Liquidation Model | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Annual home price appreciation/(depreciation) | Valuation Technique, Liquidation Model | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 1.225          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Liquidation timeline (months) | Valuation Technique, Liquidation Model | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input | month 17          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Liquidation timeline (months) | Valuation Technique, Liquidation Model | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input | month 9          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Liquidation timeline (months) | Valuation Technique, Liquidation Model | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input | month 54          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Property value | Valuation Technique, Liquidation Model | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 1,660,000          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Property value | Valuation Technique, Liquidation Model | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 24,000          
Level 3 | Residential loans, residential loans held in securitization trusts and residential loans held for sale | Property value | Valuation Technique, Liquidation Model | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 14,250,000          
Level 3 | Multi-family loans            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, at fair value $ 36,868          
Level 3 | Multi-family loans | Discount rate | Valuation Technique, Discounted Cash Flow | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.126          
Level 3 | Multi-family loans | Discount rate | Valuation Technique, Discounted Cash Flow | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.115          
Level 3 | Multi-family loans | Discount rate | Valuation Technique, Discounted Cash Flow | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input 0.148          
Level 3 | Multi-family loans | Months to assumed redemption | Valuation Technique, Discounted Cash Flow | Weighted Average            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input | month 25.8          
Level 3 | Multi-family loans | Months to assumed redemption | Valuation Technique, Discounted Cash Flow | Minimum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input | month 13          
Level 3 | Multi-family loans | Months to assumed redemption | Valuation Technique, Discounted Cash Flow | Maximum            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, measurement input | month 31          
Level 3 | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Loans receivable, at fair value $ 1,047,558          
Variable interest entity, primary beneficiary, maximum loss exposure, amount 122,100   $ 151,500      
Level 3 | Consolidated SLST | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Multi-family CDOs, at fair value $ 915,698          
Level 3 | Consolidated SLST | Loss severity | Valuation Technique, Discounted Cash Flow | Weighted Average | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.141          
Level 3 | Consolidated SLST | Loss severity | Valuation Technique, Discounted Cash Flow | Minimum | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0          
Level 3 | Consolidated SLST | Loss severity | Valuation Technique, Discounted Cash Flow | Maximum | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.188          
Level 3 | Consolidated SLST | Yield | Valuation Technique, Discounted Cash Flow | Weighted Average | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.061          
Level 3 | Consolidated SLST | Yield | Valuation Technique, Discounted Cash Flow | Minimum | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.051          
Level 3 | Consolidated SLST | Yield | Valuation Technique, Discounted Cash Flow | Maximum | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.125          
Level 3 | Consolidated SLST | Collateral prepayment rate | Valuation Technique, Discounted Cash Flow | Weighted Average | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.062          
Level 3 | Consolidated SLST | Collateral prepayment rate | Valuation Technique, Discounted Cash Flow | Minimum | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.029          
Level 3 | Consolidated SLST | Collateral prepayment rate | Valuation Technique, Discounted Cash Flow | Maximum | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.074          
Level 3 | Consolidated SLST | Collateral default rate | Valuation Technique, Discounted Cash Flow | Weighted Average | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.011          
Level 3 | Consolidated SLST | Collateral default rate | Valuation Technique, Discounted Cash Flow | Minimum | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0          
Level 3 | Consolidated SLST | Collateral default rate | Valuation Technique, Discounted Cash Flow | Maximum | Consolidated SLST | VIE, Primary Beneficiary            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Debt, measurement input 0.019