v3.26.1
Fair value measurements - Schedule of Valuation Techniques (Details)
$ in Thousands
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair value $ 309,254 $ 260,304
Level 3 | Residential mortgage loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, fair value 261,475 198,596
Level 3 | Residential mortgage loans | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, fair value $ 7,119,175 $ 7,999,619
Level 3 | Residential mortgage loans | Yield | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0569 0.0539
Level 3 | Residential mortgage loans | Yield | Minimum | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0547 0.0513
Level 3 | Residential mortgage loans | Yield | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.1200 0.1161
Level 3 | Residential mortgage loans | Yield | Maximum | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.1651 0.1810
Level 3 | Residential mortgage loans | Yield | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0737 0.0708
Level 3 | Residential mortgage loans | Yield | Weighted Average | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0599 0.0578
Level 3 | Residential mortgage loans | Projected Collateral Prepayments | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0290 0.0198
Level 3 | Residential mortgage loans | Projected Collateral Prepayments | Minimum | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0429 0.0492
Level 3 | Residential mortgage loans | Projected Collateral Prepayments | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.3935 0.3346
Level 3 | Residential mortgage loans | Projected Collateral Prepayments | Maximum | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.2200 0.2200
Level 3 | Residential mortgage loans | Projected Collateral Prepayments | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.1724 0.1606
Level 3 | Residential mortgage loans | Projected Collateral Prepayments | Weighted Average | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.1004 0.1009
Level 3 | Residential mortgage loans | Projected Collateral Losses | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0000 0.0000
Level 3 | Residential mortgage loans | Projected Collateral Losses | Minimum | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0000 0.0000
Level 3 | Residential mortgage loans | Projected Collateral Losses | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.1578 0.1829
Level 3 | Residential mortgage loans | Projected Collateral Losses | Maximum | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0172 0.0177
Level 3 | Residential mortgage loans | Projected Collateral Losses | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0138 0.0147
Level 3 | Residential mortgage loans | Projected Collateral Losses | Weighted Average | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0011 0.0009
Level 3 | Residential mortgage loans | Projected Collateral Severities | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.1000 0.0443
Level 3 | Residential mortgage loans | Projected Collateral Severities | Minimum | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.1000 0.1000
Level 3 | Residential mortgage loans | Projected Collateral Severities | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 1.0000 1.0000
Level 3 | Residential mortgage loans | Projected Collateral Severities | Maximum | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.7500 1.0000
Level 3 | Residential mortgage loans | Projected Collateral Severities | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.1907 0.1779
Level 3 | Residential mortgage loans | Projected Collateral Severities | Weighted Average | Securitized Residential Mortgage Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.2303 0.2823
Level 3 | Legacy WMC Commercial Loans | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, fair value $ 49,254 $ 55,376
Level 3 | Legacy WMC Commercial Loans | Yield | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0836 0.0595
Level 3 | Legacy WMC Commercial Loans | Yield | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.1110 0.0695
Level 3 | Legacy WMC Commercial Loans | Yield | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0926 0.0668
Level 3 | Legacy WMC Commercial Loans | Credit Spread | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0432 0.0231
Level 3 | Legacy WMC Commercial Loans | Credit Spread | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0715 0.0325
Level 3 | Legacy WMC Commercial Loans | Credit Spread | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.0516 0.0300
Level 3 | Legacy WMC Commercial Loans | Recovery Percentage | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.7219 0.6833
Level 3 | Legacy WMC Commercial Loans | Recovery Percentage | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.9805 0.9329
Level 3 | Legacy WMC Commercial Loans | Recovery Percentage | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 0.7907 0.8662
Level 3 | Non-Agency RMBS | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair value $ 241,893 $ 191,546
Level 3 | Non-Agency RMBS | Yield | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.0526 0.0483
Level 3 | Non-Agency RMBS | Yield | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.1625 0.2000
Level 3 | Non-Agency RMBS | Yield | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.0726 0.0756
Level 3 | Non-Agency RMBS | Projected Collateral Prepayments | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.0816 0.0755
Level 3 | Non-Agency RMBS | Projected Collateral Prepayments | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.2615 0.1523
Level 3 | Non-Agency RMBS | Projected Collateral Prepayments | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.1183 0.1123
Level 3 | Non-Agency RMBS | Projected Collateral Losses | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.0000 0.0000
Level 3 | Non-Agency RMBS | Projected Collateral Losses | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.0080 0.0038
Level 3 | Non-Agency RMBS | Projected Collateral Losses | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.0018 0.0006
Level 3 | Non-Agency RMBS | Projected Collateral Severities | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.1000 0.1000
Level 3 | Non-Agency RMBS | Projected Collateral Severities | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.7500 1.0000
Level 3 | Non-Agency RMBS | Projected Collateral Severities | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Debt securities, measurement input 0.2907 0.5687
Level 3 | AG Arc | Comparable Multiple    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, fair value $ 46,435 $ 50,016
Level 3 | AG Arc | Book Value Multiple | Minimum | Comparable Multiple    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 1.05 1.025
Level 3 | AG Arc | Book Value Multiple | Maximum | Comparable Multiple    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 1.05 1.025
Level 3 | AG Arc | Book Value Multiple | Weighted Average | Comparable Multiple    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Loans held-for-sale, measurement input 1.05 1.025
Level 3 | Securitized Debt | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, fair value $ (6,355,237) $ (7,177,923)
Level 3 | Securitized Debt | Yield | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.0484 0.0437
Level 3 | Securitized Debt | Yield | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.2500 0.3000
Level 3 | Securitized Debt | Yield | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.0569 0.0542
Level 3 | Securitized Debt | Projected Collateral Prepayments | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.0429 0.0492
Level 3 | Securitized Debt | Projected Collateral Prepayments | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.2200 0.2200
Level 3 | Securitized Debt | Projected Collateral Prepayments | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.1002 0.1009
Level 3 | Securitized Debt | Projected Collateral Losses | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.0000 0.0000
Level 3 | Securitized Debt | Projected Collateral Losses | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.0050 0.0050
Level 3 | Securitized Debt | Projected Collateral Losses | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.0010 0.0008
Level 3 | Securitized Debt | Projected Collateral Severities | Minimum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.1000 0.1000
Level 3 | Securitized Debt | Projected Collateral Severities | Maximum | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.7500 1.0000
Level 3 | Securitized Debt | Projected Collateral Severities | Weighted Average | Discounted Cash Flow    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Long-term debt, measurement input 0.2312 0.2779