Quarterly report pursuant to Section 13 or 15(d)

Fair Value - Summary of Fair Value and Unpaid Principal Balance ("UPB") of Financial Assets and Liabilities With Elected Fair Value Option (Details)

v3.23.3
Fair Value - Summary of Fair Value and Unpaid Principal Balance ("UPB") of Financial Assets and Liabilities With Elected Fair Value Option (Details) - USD ($)
$ in Thousands
Sep. 30, 2023
Dec. 31, 2022
Estimated Fair Value    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option $ 17,185,552 $ 11,114,100
Estimated Fair Value | Loans held for investment | Reverse mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 463,125 771,724
Estimated Fair Value | Loans held for investment | Commercial mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 4,194 136,274
Estimated Fair Value | Loans held for sale | Commercial mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 3,392 161,861
Estimated Fair Value | Loans held for sale | Residential mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 20,564 12,123
Estimated Fair Value | Reverse mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option   9,356
Estimated Fair Value | HMBS related obligations    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option 16,978,168 10,996,755
Estimated Fair Value | Nonrecourse debt in consolidated VIE trusts    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option 7,780,197 7,175,857
Estimated Fair Value | Nonrecourse commercial loan financing liability    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option 32,373 106,758
Estimated Fair Value | Nonrecourse MSR financing liability    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option   60,562
Estimated Fair Value | Sale commitments - home improvement loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option 1,095  
Estimated Fair Value | Reverse mortgage loans | Loans held for investment, subject to nonrecourse debt    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 7,727,659 7,065,477
Estimated Fair Value | Commercial mortgage loans | Loans held for investment, subject to nonrecourse debt    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 185,100 389,161
Unpaid Principal Balance    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 16,522,369 10,719,000
Unpaid Principal Balance | Loans held for investment | Reverse mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 487,710 724,800
Unpaid Principal Balance | Loans held for investment | Commercial mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 4,513 143,373
Unpaid Principal Balance | Loans held for sale | Commercial mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 3,772 173,112
Unpaid Principal Balance | Loans held for sale | Residential mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 28,051 15,529
Unpaid Principal Balance | Reverse mortgage loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option   9,356
Unpaid Principal Balance | HMBS related obligations    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option 16,522,369 10,719,000
Unpaid Principal Balance | Nonrecourse debt in consolidated VIE trusts    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option 8,550,740 7,819,992
Unpaid Principal Balance | Nonrecourse commercial loan financing liability    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option 30,927 105,291
Unpaid Principal Balance | Nonrecourse MSR financing liability    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option   60,562
Unpaid Principal Balance | Sale commitments - home improvement loans    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Liabilities at fair value under the fair value option 1,095  
Unpaid Principal Balance | Reverse mortgage loans | Loans held for investment, subject to nonrecourse debt    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option 8,200,222 7,240,125
Unpaid Principal Balance | Commercial mortgage loans | Loans held for investment, subject to nonrecourse debt    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Assets at fair value under the fair value option $ 191,111 $ 405,970