v3.26.3
Derivative and Credit Risk Transfer Strip Assets and Liabilities - Summary of Derivative Assets, Financial Instruments and Collateral Held by Counterparty (Detail) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Offsetting Assets [Line Items]    
Total derivative assets after netting $ 53,001 $ 49,696
Financial instruments 0 0
Cash collateral received 0 0
Net amount 53,001 49,696
Credit Risk Transfer Derivatives [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 30,695 32,659
Financial instruments 0 0
Cash collateral received 0 0
Net amount 30,695 32,659
Metro Life Ins Co [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 7,639 151
Financial instruments 0 0
Cash collateral received 0 0
Net amount 7,639 151
Bank of America, N.A. [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 6,163 4,745
Financial instruments 0 0
Cash collateral received 0 0
Net amount 6,163 4,745
RJ O'Brien & Associates, LLC [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 5,654 5,398
Financial instruments 0 0
Cash collateral received 0 0
Net amount 5,654 5,398
Morgan Stanley & Co. LLC [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 1,078 3,500
Financial instruments 0 0
Cash collateral received 0 0
Net amount 1,078 3,500
Nomura Holdings America Inc [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 382 137
Financial instruments 0 0
Cash collateral received 0 0
Net amount 382 137
Ares Management Corporation [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 334 0
Financial instruments 0 0
Cash collateral received 0 0
Net amount 334 0
J.P. Morgan Securities LLC [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 126 102
Financial instruments 0 0
Cash collateral received 0 0
Net amount 126 102
BNP Paribas [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 46 236
Financial instruments 0 0
Cash collateral received 0 0
Net amount 46 236
Other [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 884 2,768
Financial instruments 0 0
Cash collateral received 0 0
Net amount 884 2,768
Pennymac Financial Services Inc [Member]    
Offsetting Assets [Line Items]    
Total derivative assets after netting 5,668 6,247
Financial instruments 0 0
Cash collateral received 0 0
Net amount $ 5,668 $ 6,247