v3.26.3
Segments - Financial Highlights by Segment (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Net investment income:          
Net loan servicing fees $ 241,879 $ 15,429 $ 365,506 $ 12,166  
Net (losses) gains on investments and financings          
Mortgage-backed securities (166,947) 37,572 (199,928) 116,991  
Loans held for investment (5,320) 12,773 3,277 10,897  
Credit risk transfer arrangements 10,002 13,742 33,624 32,192  
Net (losses) gains on investments and financings (162,265) 64,087 (163,027) 160,080  
Net gains on loans held for sale 5,196 14,857 43,398 45,007  
Net interest (expense) income:          
Interest income 314,402 230,088 894,743 602,660  
Interest expense 364,290 228,394 955,385 615,680  
Net interest (expense) income (49,888) 1,694 (60,642) (13,020)  
Other 1,322 3,165 5,872 9,665  
Net investment income 36,244 99,232 191,107 213,898  
Expenses:          
Professional services 12,503 8,608 37,631 23,952  
Compensation 2,628 2,817 8,994 8,623  
Loan collection and liquidation 2,622 1,503 6,426 5,857  
Safekeeping 921 1,194 2,707 3,532  
Loan origination 0 794 227 2,146  
Other 3,594 3,232 13,736 9,638  
Total expenses 52,685 52,234 163,833 156,193  
(Loss) income before provision for (benefit from) income taxes (16,441) 46,998 27,274 57,705  
Total assets at end of quarter 26,853,863 18,525,671 26,853,863 18,525,671 $ 21,346,882
PennyMac Financial Services, Inc. [Member]          
Net (losses) gains on investments and financings          
Net gains on loans held for sale 0 531 0 5,204  
Expenses:          
Loan servicing fees 20,449 21,012 59,812 64,386  
Management fees 6,762 6,912 20,334 20,793  
Loan fulfillment fees 3,206 6,162 13,966 17,266  
Reportable Segment [Member]          
Net investment income:          
Net loan servicing fees 241,879 15,429 365,506 12,166  
Net (losses) gains on investments and financings          
Mortgage-backed securities (166,947) 37,572 (199,928) 116,991  
Loans held for investment (5,320) 12,773 3,277 10,897  
Credit risk transfer arrangements 10,002 13,742 33,624 32,192  
Net (losses) gains on investments and financings (162,265) 64,087 (163,027) 160,080  
Net gains on loans held for sale 5,196 14,857 43,398 45,007  
Net interest (expense) income:          
Interest income 312,474 227,793 887,585 594,786  
Interest expense 362,962 227,035 950,088 611,717  
Net interest (expense) income (50,488) 758 (62,503) (16,931)  
Other 1,322 3,165 5,872 9,665  
Net investment income 35,644 98,296 189,246 209,987  
Expenses:          
Professional services 10,783 6,589 30,876 17,850  
Compensation 0 0 0 0  
Loan collection and liquidation 2,622 1,503 6,426 5,857  
Safekeeping 921 1,194 2,707 3,532  
Loan origination 0 794 227 2,146  
Other 1,353 698 6,686 2,175  
Total expenses 39,334 37,952 120,700 113,212  
(Loss) income before provision for (benefit from) income taxes (3,690) 60,344 68,546 96,775  
Total assets at end of quarter 26,532,183 18,081,086 26,532,183 18,081,086  
Reportable Segment [Member] | PennyMac Financial Services, Inc. [Member]          
Expenses:          
Loan servicing fees 20,449 21,012 59,812 64,386  
Management fees 0 0 0 0  
Loan fulfillment fees 3,206 6,162 13,966 17,266  
Corporate [Member]          
Net investment income:          
Net loan servicing fees 0 0 0 0  
Net (losses) gains on investments and financings          
Mortgage-backed securities 0 0 0 0  
Loans held for investment 0 0 0 0  
Credit risk transfer arrangements 0 0 0 0  
Net (losses) gains on investments and financings 0 0 0 0  
Net gains on loans held for sale 0 0 0 0  
Net interest (expense) income:          
Interest income 1,928 2,295 7,158 7,874  
Interest expense 1,328 1,359 5,297 3,963  
Net interest (expense) income 600 936 1,861 3,911  
Other 0 0 0 0  
Net investment income 600 936 1,861 3,911  
Expenses:          
Professional services 1,720 2,019 6,755 6,102  
Compensation 2,628 2,817 8,994 8,623  
Loan collection and liquidation 0 0 0 0  
Safekeeping 0 0 0 0  
Loan origination 0 0 0 0  
Other 2,241 2,534 7,050 7,463  
Total expenses 13,351 14,282 43,133 42,981  
(Loss) income before provision for (benefit from) income taxes (12,751) (13,346) (41,272) (39,070)  
Total assets at end of quarter 321,680 444,585 321,680 444,585  
Corporate [Member] | PennyMac Financial Services, Inc. [Member]          
Expenses:          
Loan servicing fees 0 0 0 0  
Management fees 6,762 6,912 20,334 20,793  
Loan fulfillment fees 0 0 0 0  
Credit Sensitive Strategies [Member] | Reportable Segment [Member]          
Net investment income:          
Net loan servicing fees 0 0 0 0  
Net (losses) gains on investments and financings          
Mortgage-backed securities (67) (817) (75) (1,321)  
Loans held for investment (54,345) 4,655 (51,944) 6,465  
Credit risk transfer arrangements 10,002 13,742 33,624 32,192  
Net (losses) gains on investments and financings (44,410) 17,580 (18,395) 37,336  
Net gains on loans held for sale 0 0 0 0  
Net interest (expense) income:          
Interest income 23,689 20,912 64,465 61,432  
Interest expense 20,933 19,615 59,746 56,557  
Net interest (expense) income 2,756 1,297 4,719 4,875  
Other (52) (28) (161) (169)  
Net investment income (41,706) 18,849 (13,837) 42,042  
Expenses:          
Professional services 0 0 0 0  
Compensation 0 0 0 0  
Loan collection and liquidation 6 9 25 72  
Safekeeping 0 0 0 0  
Loan origination 0 0 0 0  
Other 57 85 197 267  
Total expenses 64 95 225 344  
(Loss) income before provision for (benefit from) income taxes (41,770) 18,754 (14,062) 41,698  
Total assets at end of quarter 1,870,296 1,442,766 1,870,296 1,442,766  
Credit Sensitive Strategies [Member] | Reportable Segment [Member] | PennyMac Financial Services, Inc. [Member]          
Expenses:          
Loan servicing fees 1 1 3 5  
Management fees 0 0 0 0  
Loan fulfillment fees 0 0 0 0  
Interest Rate Sensitive Strategies [Member] | Reportable Segment [Member]          
Net investment income:          
Net loan servicing fees 241,879 15,429 365,506 12,166  
Net (losses) gains on investments and financings          
Mortgage-backed securities (166,880) 38,389 (199,853) 118,312  
Loans held for investment 49,025 8,118 55,221 4,432  
Credit risk transfer arrangements 0 0 0 0  
Net (losses) gains on investments and financings (117,855) 46,507 (144,632) 122,744  
Net gains on loans held for sale 0 0 0 0  
Net interest (expense) income:          
Interest income 241,987 173,810 693,310 431,199  
Interest expense 304,760 179,206 789,058 469,151  
Net interest (expense) income (62,773) (5,396) (95,748) (37,952)  
Other 0 0 0 0  
Net investment income 61,251 56,540 125,126 96,958  
Expenses:          
Professional services 0 0 0 0  
Compensation 0 0 0 0  
Loan collection and liquidation 2,616 1,494 6,401 5,785  
Safekeeping 914 1,112 2,607 3,290  
Loan origination 0 0 0 0  
Other 1,263 577 3,318 1,520  
Total expenses 25,241 24,194 72,135 74,976  
(Loss) income before provision for (benefit from) income taxes 36,010 32,346 52,991 21,982  
Total assets at end of quarter 21,681,759 14,161,304 21,681,759 14,161,304  
Interest Rate Sensitive Strategies [Member] | Reportable Segment [Member] | PennyMac Financial Services, Inc. [Member]          
Expenses:          
Loan servicing fees 20,448 21,011 59,809 64,381  
Management fees 0 0 0 0  
Loan fulfillment fees 0 0 0 0  
Aggregation and Securitization [Member] | Reportable Segment [Member]          
Net investment income:          
Net loan servicing fees 0 0 0 0  
Net (losses) gains on investments and financings          
Mortgage-backed securities 0 0 0 0  
Loans held for investment 0 0 0 0  
Credit risk transfer arrangements 0 0 0 0  
Net (losses) gains on investments and financings 0 0 0 0  
Net gains on loans held for sale 5,196 14,857 43,398 45,007  
Net interest (expense) income:          
Interest income 46,798 33,071 129,810 102,155  
Interest expense 37,269 28,214 101,284 86,009  
Net interest (expense) income 9,529 4,857 28,526 16,146  
Other 1,374 3,193 6,033 9,834  
Net investment income 16,099 22,907 77,957 70,987  
Expenses:          
Professional services 10,783 6,589 30,876 17,850  
Compensation 0 0 0 0  
Loan collection and liquidation 0 0 0 0  
Safekeeping 7 82 100 242  
Loan origination 0 794 227 2,146  
Other 33 36 3,171 388  
Total expenses 14,029 13,663 48,340 37,892  
(Loss) income before provision for (benefit from) income taxes 2,070 9,244 29,617 33,095  
Total assets at end of quarter 2,980,128 2,477,016 2,980,128 2,477,016  
Aggregation and Securitization [Member] | Reportable Segment [Member] | PennyMac Financial Services, Inc. [Member]          
Expenses:          
Loan servicing fees 0 0 0 0  
Management fees 0 0 0 0  
Loan fulfillment fees $ 3,206 $ 6,162 $ 13,966 $ 17,266