v3.26.1
Fair Value - Financial Statement Items Measured at Fair Value on a Recurring Basis (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Assets:    
Short-term investment at fair value $ 434,220 $ 410,037
Principal-only stripped mortgage-backed securities at fair value pledged to creditors 659,235 722,528
Loans held for sale 9,954,495 9,123,410
Derivative assets:    
Derivative asset, before netting 384,325 222,297
Netting (107,616) (36,779)
Total derivative assets 276,709 185,518
Investment in PennyMac Mortgage Investment Trust 875 941
Derivative liabilities:    
Derivative liability, before netting 145,894 54,797
Netting (79,065) (45,238)
Net amounts of liabilities presented in the consolidated balance sheet 66,829 9,559
Derivative liabilities to PennyMac Mortgage Investment Trust 3,823 6,247
Mortgage servicing liabilities 1,568 1,572
PennyMac Mortgage Investment Trust    
Derivative assets:    
Total derivative assets 5,886 2,257
Recurring basis    
Assets:    
Short-term investment at fair value 434,220 410,037
Principal-only stripped mortgage-backed securities at fair value pledged to creditors 659,235 722,528
Loans held for sale 9,954,495 9,123,410
Derivative assets:    
Derivative asset, before netting 384,325 222,297
Netting (107,616) (36,779)
Total derivative assets 276,709 185,518
Investment in PennyMac Mortgage Investment Trust   941
Total assets 21,480,456 20,043,632
Derivative liabilities:    
Derivative liability, before netting 145,894 54,797
Netting (79,065) (45,238)
Net amounts of liabilities presented in the consolidated balance sheet 66,829 9,559
Mortgage servicing liabilities 1,568 1,572
Total liabilities 72,220 17,378
Recurring basis | Related Party | PennyMac Mortgage Investment Trust    
Derivative assets:    
Derivative asset, before netting 5,901 2,399
Netting (15) (142)
Total derivative assets 5,886 2,257
Mortgage servicing rights 10,149,036 9,598,941
Investment in PennyMac Mortgage Investment Trust 875  
Derivative liabilities:    
Derivative liability, before netting 3,838 6,389
Netting (15) (142)
Total liabilities 3,823 6,247
Recurring basis | Interest rate lock commitments    
Derivative assets:    
Derivative asset, before netting 138,031 131,536
Derivative liabilities:    
Derivative liability, before netting 35,368 4,260
Recurring basis | Interest rate lock commitments | Related Party | PennyMac Mortgage Investment Trust    
Derivative assets:    
Derivative asset, before netting 5,886 2,257
Derivative liabilities:    
Derivative liability, before netting 2,613 4,605
Recurring basis | Forward contracts | Purchases    
Derivative assets:    
Derivative asset, before netting 24,588 49,499
Derivative liabilities:    
Derivative liability, before netting 67,863 2,845
Recurring basis | Forward contracts | Sales    
Derivative assets:    
Derivative asset, before netting 165,645 16,399
Derivative liabilities:    
Derivative liability, before netting 42,663 47,692
Recurring basis | Forward contracts | Sales | Related Party | PennyMac Mortgage Investment Trust    
Derivative assets:    
Derivative asset, before netting 15 142
Derivative liabilities:    
Derivative liability, before netting 1,225 1,784
Recurring basis | MBS put options    
Derivative assets:    
Derivative asset, before netting 4,840  
Recurring basis | Put options on interest rate | Purchases    
Derivative assets:    
Derivative asset, before netting 41,688 2,086
Recurring basis | Call options on interest rate | Purchases    
Derivative assets:    
Derivative asset, before netting 9,414 8
Recurring basis | Total return swap    
Derivative assets:    
Derivative asset, before netting 119 22,769
Recurring basis | Level 1    
Assets:    
Short-term investment at fair value 434,220 410,037
Derivative assets:    
Derivative asset, before netting 51,102 24,855
Total derivative assets 51,102 24,855
Investment in PennyMac Mortgage Investment Trust   941
Total assets 486,197 435,833
Recurring basis | Level 1 | Related Party | PennyMac Mortgage Investment Trust    
Derivative assets:    
Investment in PennyMac Mortgage Investment Trust 875  
Recurring basis | Level 1 | Put options on interest rate | Purchases    
Derivative assets:    
Derivative asset, before netting 41,688 2,086
Recurring basis | Level 1 | Call options on interest rate | Purchases    
Derivative assets:    
Derivative asset, before netting 9,414  
Recurring basis | Level 1 | Total return swap    
Derivative assets:    
Derivative asset, before netting   22,769
Recurring basis | Level 2    
Assets:    
Principal-only stripped mortgage-backed securities at fair value pledged to creditors 659,235 722,528
Loans held for sale 9,525,538 8,815,699
Derivative assets:    
Derivative asset, before netting 195,192 65,906
Total derivative assets 195,192 65,906
Total assets 10,379,980 9,604,275
Derivative liabilities:    
Derivative liability, before netting 110,526 50,537
Net amounts of liabilities presented in the consolidated balance sheet 110,526 50,537
Total liabilities 111,751 52,321
Recurring basis | Level 2 | Related Party | PennyMac Mortgage Investment Trust    
Derivative assets:    
Derivative asset, before netting 15 142
Total derivative assets 15 142
Derivative liabilities:    
Derivative liability, before netting 1,225 1,784
Total liabilities 1,225 1,784
Recurring basis | Level 2 | Forward contracts | Purchases    
Derivative assets:    
Derivative asset, before netting 24,588 49,499
Derivative liabilities:    
Derivative liability, before netting 67,863 2,845
Recurring basis | Level 2 | Forward contracts | Sales    
Derivative assets:    
Derivative asset, before netting 165,645 16,399
Derivative liabilities:    
Derivative liability, before netting 42,663 47,692
Recurring basis | Level 2 | Forward contracts | Sales | Related Party | PennyMac Mortgage Investment Trust    
Derivative assets:    
Derivative asset, before netting 15 142
Derivative liabilities:    
Derivative liability, before netting 1,225 1,784
Recurring basis | Level 2 | MBS put options    
Derivative assets:    
Derivative asset, before netting 4,840  
Recurring basis | Level 2 | Call options on interest rate | Purchases    
Derivative assets:    
Derivative asset, before netting   8
Recurring basis | Level 2 | Total return swap    
Derivative assets:    
Derivative asset, before netting 119  
Recurring basis | Level 3    
Assets:    
Loans held for sale 428,957 307,711
Derivative assets:    
Derivative asset, before netting 138,031 131,536
Total derivative assets 138,031 131,536
Total assets 10,721,910 10,040,445
Derivative liabilities:    
Derivative liability, before netting 35,368 4,260
Net amounts of liabilities presented in the consolidated balance sheet 35,368 4,260
Mortgage servicing liabilities 1,568 1,572
Total liabilities 39,549 10,437
Recurring basis | Level 3 | Related Party | PennyMac Mortgage Investment Trust    
Derivative assets:    
Derivative asset, before netting 5,886 2,257
Total derivative assets 5,886 2,257
Mortgage servicing rights 10,149,036 9,598,941
Derivative liabilities:    
Derivative liability, before netting 2,613 4,605
Total liabilities 2,613 4,605
Recurring basis | Level 3 | Interest rate lock commitments    
Derivative assets:    
Derivative asset, before netting 138,031 131,536
Derivative liabilities:    
Derivative liability, before netting 35,368 4,260
Recurring basis | Level 3 | Interest rate lock commitments | Related Party | PennyMac Mortgage Investment Trust    
Derivative assets:    
Derivative asset, before netting 5,886 2,257
Derivative liabilities:    
Derivative liability, before netting $ 2,613 $ 4,605