Fair Value - Summary of Changes in Items Measured Using Level 3 Inputs on Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Assets:
Amounts received pursuant to sales of loans	$ 30,981	$ 44,030	$ 71,262	$ 91,039
Changes in fair value included in income arising from:
Mortgage servicing rights relating to delinquent loans to Agency			2,402	391
Interest Rate Lock Commitments with PFSI [Member]
Assets:
Beginning balance			2,348
Changes in fair value included in income arising from:
Ending balance	2,945		2,945
Recurring [Member]
Assets:
Beginning balance	3,721,981	3,875,551	3,751,498	3,989,252
Purchases and issuances	14,251	6,656	23,122	11,283
Repayments and sales	(20,100)	(18,854)	(40,214)	(38,848)
Accrual of unearned discount	1,845	2,165	3,810	4,450
Amounts received pursuant to sales of loans	30,981	44,030	71,262	91,039
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0	0	0
Other factors	(71,577)	(49,172)	(125,437)	(189,206)
Total	(71,577)	(49,172)	(125,437)	(189,206)
Interest rate lock commitments to loans held for sale	(3,230)	(6,216)	(10,185)	(14,031)
Mortgage servicing rights relating to delinquent loans to Agency	2,107	170	2,402	391
Ending balance	3,676,258	3,854,330	3,676,258	3,854,330
Changes in fair value recognized during the quarter/period relating to assets	(79,826)	(60,046)	(140,852)	(220,141)
Recurring [Member] \| Credit Risk Transfer Strips [Member]
Assets:
Beginning balance	(4,062)	(15,885)	(5,999)	(4,060)
Purchases and issuances	0	0	0	0
Repayments and sales	(8,885)	(10,068)	(17,309)	(19,845)
Accrual of unearned discount	0	0	0	0
Amounts received pursuant to sales of loans	0	0	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0	0	0
Other factors	7,519	15,474	17,880	13,426
Total	7,519	15,474	17,880	13,426
Interest rate lock commitments to loans held for sale	0	0	0	0
Mortgage servicing rights relating to delinquent loans to Agency	0	0	0	0
Ending balance	(5,428)	(10,479)	(5,428)	(10,479)
Changes in fair value recognized during the quarter/period relating to assets	(1,125)	5,524	681	(6,301)
Recurring [Member] \| Credit Risk Transfer Derivatives [Member]
Assets:
Beginning balance	30,174	28,474	32,659	29,377
Purchases and issuances	0	0	0	0
Repayments and sales	(2,132)	(2,702)	(4,749)	(5,585)
Accrual of unearned discount	0	0	0	0
Amounts received pursuant to sales of loans	0	0	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0	0	0
Other factors	2,259	5,375	2,391	7,355
Total	2,259	5,375	2,391	7,355
Interest rate lock commitments to loans held for sale	0	0	0	0
Mortgage servicing rights relating to delinquent loans to Agency	0	0	0	0
Ending balance	30,301	31,147	30,301	31,147
Changes in fair value recognized during the quarter/period relating to assets	215	2,743	(2,201)	1,920
Recurring [Member] \| Loans Held for Investment [Member]
Assets:
Beginning balance	1,650	1,815	1,705	1,866
Purchases and issuances	0	0	0	0
Repayments and sales	(54)	(20)	(70)	(40)
Accrual of unearned discount	0	0	0	0
Amounts received pursuant to sales of loans	0	0	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0	0	0
Other factors	(4)	59	(43)	28
Total	(4)	59	(43)	28
Interest rate lock commitments to loans held for sale	0	0	0	0
Mortgage servicing rights relating to delinquent loans to Agency	0	0	0	0
Ending balance	1,592	1,854	1,592	1,854
Changes in fair value recognized during the quarter/period relating to assets	(7)	58	(47)	27
Recurring [Member] \| Mortgage servicing rights [Member]
Assets:
Beginning balance	3,623,979	3,770,034	3,644,702	3,867,394
Purchases and issuances	0	0	0	0
Repayments and sales	0	0	0	0
Accrual of unearned discount	0	0	0	0
Amounts received pursuant to sales of loans	30,981	44,030	71,262	91,039
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0	0	0
Other factors	(81,464)	(75,128)	(142,763)	(219,718)
Total	(81,464)	(75,128)	(142,763)	(219,718)
Interest rate lock commitments to loans held for sale	0	0	0	0
Mortgage servicing rights relating to delinquent loans to Agency	2,107	170	2,402	391
Ending balance	3,575,603	3,739,106	3,575,603	3,739,106
Changes in fair value recognized during the quarter/period relating to assets	(81,464)	(75,128)	(142,763)	(219,718)
Recurring [Member] \| Loans Held For Sale [Member]
Assets:
Beginning balance	2,084	5,451	3,581	7,971
Purchases and issuances	5,293	3,103	8,894	3,131
Repayments and sales	(5,075)	(1,540)	(10,025)	(4,218)
Accrual of unearned discount	0	0	0	0
Amounts received pursuant to sales of loans	0	0	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0	0	0
Other factors	9	151	(139)	281
Total	9	151	(139)	281
Interest rate lock commitments to loans held for sale	0	0	0	0
Mortgage servicing rights relating to delinquent loans to Agency	0	0	0	0
Ending balance	2,311	7,165	2,311	7,165
Changes in fair value recognized during the quarter/period relating to assets	(4)	(96)	(150)	(56)
Recurring [Member] \| Interest Rate Lock Commitments with PFSI [Member]
Assets:
Beginning balance	(3,273)	4,619	2,348	444
Purchases and issuances	8,958	3,553	14,228	8,152
Repayments and sales	0	0	0	0
Accrual of unearned discount	0	0	0	0
Amounts received pursuant to sales of loans	0	0	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0	0	0
Other factors	490	4,529	(3,446)	11,920
Total	490	4,529	(3,446)	11,920
Interest rate lock commitments to loans held for sale	(3,230)	(6,216)	(10,185)	(14,031)
Mortgage servicing rights relating to delinquent loans to Agency	0	0	0	0
Ending balance	2,945	6,485	2,945	6,485
Changes in fair value recognized during the quarter/period relating to assets	2,945	6,485	2,945	6,485
Recurring [Member] \| Interest-only security payable [Member]
Liabilities:
Beginning balance	34,232	35,954	37,650	34,222
Changes in instrument-specific credit risk\Other factors	67	599	(3,351)	2,331
Ending balance	34,299	36,553	34,299	36,553
Changes in fair value recognized during the quarter/period relating to liability	67	599	(3,351)	2,331
Recurring [Member] \| Interest-only security payable [Member] \| Credit Risk [Member]
Liabilities:
Changes in instrument-specific credit risk\Other factors	0	0	0	0
Recurring [Member] \| Interest-only security payable [Member] \| Other Factors [Member]
Liabilities:
Changes in instrument-specific credit risk\Other factors	67	599	(3,351)	2,331
Recurring [Member] \| Interest-Only Stripped Mortgage-Backed Securities [Member]
Assets:
Beginning balance	71,429	81,043	72,502	86,260
Purchases and issuances	0	0	0	0
Repayments and sales	(3,954)	(4,524)	(8,061)	(9,160)
Accrual of unearned discount	1,845	2,165	3,810	4,450
Amounts received pursuant to sales of loans	0	0	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0	0	0
Other factors	(386)	368	683	(2,498)
Total	(386)	368	683	(2,498)
Interest rate lock commitments to loans held for sale	0	0	0	0
Mortgage servicing rights relating to delinquent loans to Agency	0	0	0	0
Ending balance	68,934	79,052	68,934	79,052
Changes in fair value recognized during the quarter/period relating to assets	$ (386)	$ 368	$ 683	$ (2,498)

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Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held.

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Amount of unrealized gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3) and still held.

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Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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