v3.26.3
Derivative and Credit Risk Transfer Strip Assets and Liabilities - Derivative Assets and Derivative and Credit Risk Transfer Strip Liabilities at Fair Value and Related Margin Deposits (Detail) - USD ($)
Sep. 30, 2026
Dec. 31, 2025
Derivatives Fair Value [Line Items]    
Margin deposits (received from) placed with derivative counterparties included in derivative balances above, net $ (117,134,000) $ 21,710,000
Derivative assets pledged to secure:    
Assets sold under agreements to repurchase and Notes payable secured by credit risk transfer and mortgag servicing assets 2,503,473,000 2,258,128,000
Derivative assets related to CRT Derivatives [Member]    
Derivative assets pledged to secure:    
Assets sold under agreements to repurchase and Notes payable secured by credit risk transfer and mortgag servicing assets 30,695,000 32,659,000
Penny Mac Financial Services Affiliated Entity [Member]    
Derivatives Fair Value [Line Items]    
Total derivatives assets before netting 5,832,000 6,389,000
Derivative assets, Netting (164,000) (142,000)
Total derivative assets after netting 5,668,000 6,247,000
Derivative assets pledged to secure:    
Total derivative liabilities 16,620,000 2,399,000
Derivative liabilities, Netting (164,000) (142,000)
Total derivative liabilities after netting 16,456,000 2,257,000
Nonaffiliates [Member]    
Derivatives Fair Value [Line Items]    
Total derivatives assets before netting 180,190,000 44,551,000
Derivative assets, Netting (127,189,000) 5,145,000
Total derivative assets after netting 53,001,000 49,696,000
Derivative assets pledged to secure:    
Total derivative liabilities 16,157,000 17,498,000
Derivative liabilities, Netting (10,055,000) (16,565,000)
Total derivative liabilities after netting 6,102,000 933,000
Nonaffiliates [Member] | Credit Risk Transfer Derivatives [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [1],[2] 2,906,185,000 455,682,000
Total derivatives assets before netting [1] 30,695,000 32,659,000
Derivative assets pledged to secure:    
Total derivative liabilities [1] 0 0
Forward Purchase Contracts [Member] | Penny Mac Financial Services Affiliated Entity [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [2] 311,414,000 250,638,000
Total derivatives assets before netting 5,462,000 1,784,000
Derivative assets pledged to secure:    
Total derivative liabilities 164,000 142,000
Forward Purchase Contracts [Member] | Nonaffiliates [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [1],[2] 2,028,054,000 3,703,628,000
Total derivatives assets before netting [1] 0 4,113,000
Derivative assets pledged to secure:    
Total derivative liabilities [1] 13,166,000 158,000
Forward Sale Contracts [Member] | Nonaffiliates [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [1],[2] 5,507,527,000 7,933,760,000
Total derivatives assets before netting [1] 89,048,000 2,381,000
Derivative assets pledged to secure:    
Total derivative liabilities [1] 2,959,000 17,340,000
Interest Rate Lock Commitments [Member] | Penny Mac Financial Services Affiliated Entity [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [2] 883,146,000 1,207,859,000
Total derivatives assets before netting 370,000 4,605,000
Derivative assets pledged to secure:    
Total derivative liabilities 16,456,000 2,257,000
Call Options on Interest Rate Futures Purchase Contracts [Member] | Nonaffiliates [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [1],[2] 187,500,000 3,250,000,000
Total derivatives assets before netting [1] 88,000 1,289,000
Derivative assets pledged to secure:    
Total derivative liabilities [1] 0 0
Put Options On Interest Rate Futures Purchase Contracts | Nonaffiliates [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [1],[2] 187,500,000 2,500,000,000
Total derivatives assets before netting [1] 5,566,000 4,109,000
Derivative assets pledged to secure:    
Total derivative liabilities [1] 0 0
Swap Futures [Member] | Nonaffiliates [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [1],[2] 216,800,000 751,200,000
Total derivatives assets before netting [1] 0 0
Derivative assets pledged to secure:    
Total derivative liabilities [1] 0 0
Swaptions [Member] | Nonaffiliates [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [1],[2] 2,000,000,000 0
Total derivatives assets before netting [1] 54,793,000 0
Derivative assets pledged to secure:    
Total derivative liabilities [1] 32,000 0
Bond Futures [Member] | Nonaffiliates [Member]    
Derivatives Fair Value [Line Items]    
Notional amount [1],[2] 3,116,000,000 1,896,100,000
Total derivatives assets before netting [1] 0 0
Derivative assets pledged to secure:    
Total derivative liabilities [1] $ 0 $ 0
[1] All hedging derivatives are interest rate derivatives that are used as economic hedges.
[2] Notional amounts provide an indication of the volume of the Company’s derivative activity.