v3.25.2
Derivative and Credit Risk Transfer Strip Assets and Liabilities - Summary of Derivative Liabilities, Financial Liabilities and Collateral Pledged by Counterparty (Detail) - Unpaid Principal Balance Before Unamortized Debt Issuance Costs Adjustment [Member] - USD ($)
$ in Thousands
Jun. 30, 2025
Dec. 31, 2024
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet $ 6,836,081 $ 6,512,706
Gross amounts not offset in the consolidated balance sheet, Financial instruments (6,833,086) (6,509,415)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 2,995 3,291
Interest Rate Lock Commitments [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 181 3,118
Gross amounts not offset in the consolidated balance sheet, Financial instruments 0 0
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 181 3,118
J.P. Morgan Securities LLC [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 1,523,520 1,695,007
Gross amounts not offset in the consolidated balance sheet, Financial instruments (1,523,520) (1,695,007)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
Bank of America, N.A. [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 791,070 787,883
Gross amounts not offset in the consolidated balance sheet, Financial instruments (791,070) (787,883)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
Wells Fargo Securities L L C | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 702,271 670,605
Gross amounts not offset in the consolidated balance sheet, Financial instruments (702,271) (670,605)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
Barclays Capital Inc. [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 691,210 545,678
Gross amounts not offset in the consolidated balance sheet, Financial instruments (690,578) (545,678)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 632 0
Goldman Sachs & Co. LLC [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 605,240 311,997
Gross amounts not offset in the consolidated balance sheet, Financial instruments (605,240) (311,997)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
Atlas Securitized Products, L.P. [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 592,090 609,780
Gross amounts not offset in the consolidated balance sheet, Financial instruments (592,090) (609,780)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
Citigroup Global Markets Inc. [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 454,057 431,201
Gross amounts not offset in the consolidated balance sheet, Financial instruments (454,057) (431,201)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
RBC Capital Markets, L.P. [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 362,033 353,765
Gross amounts not offset in the consolidated balance sheet, Financial instruments (362,033) (353,765)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
Santander US Capital [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 356,698 362,196
Gross amounts not offset in the consolidated balance sheet, Financial instruments (356,698) (362,196)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
Morgan Stanley & Co. LLC [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 244,469 280,561
Gross amounts not offset in the consolidated balance sheet, Financial instruments (244,469) (280,561)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
Daiwa Capital Markets [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 206,910 230,033
Gross amounts not offset in the consolidated balance sheet, Financial instruments (206,910) (230,033)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 0
BNP Paribas [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 113,354 59,729
Gross amounts not offset in the consolidated balance sheet, Financial instruments (112,939) (59,729)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 415 0
Mizuho Financial Group [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 87,675 98,196
Gross amounts not offset in the consolidated balance sheet, Financial instruments (87,675) (98,121)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 75
Bank of Montreal [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 67,368 72,859
Gross amounts not offset in the consolidated balance sheet, Financial instruments (67,187) (72,859)
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 181 0
Nomura Holdings America, Inc [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 36,349 36
Gross amounts not offset in the consolidated balance sheet, Financial instruments (36,349) 0
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount 0 36
Other [Member] | Security Sold Under Agreements to Repurchase [Member]    
Offsetting Liabilities [Line Items]    
Net amount of liabilities presented in the consolidated balance sheet 1,586 62
Gross amounts not offset in the consolidated balance sheet, Financial instruments 0 0
Gross amounts not offset in the consolidated balance sheet, Cash collateral pledged 0 0
Net amount $ 1,586 $ 62