Fair Value - Summary of Changes in Items Measured Using Level 3 Inputs on Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Assets:
Amounts received pursuant to sales of loans	$ 40,281	$ 47,009
Changes in fair value included in income arising from:
Mortgage servicing rights relating to delinquent loans to Agency	295	221
Interest Rate Lock Commitments with PFSI [Member]
Assets:
Beginning balance	2,348
Liabilities:
Ending balance	3,273
Recurring [Member]
Assets:
Beginning balance	3,751,498	3,989,252
Purchases and issuances	8,871	4,627
Repayments and sales	(20,114)	(19,994)
Accrual of unearned discount	1,965	2,285
Amounts received pursuant to sales of loans	40,281	47,009
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0
Other factors	(53,860)	140,034
Total	(53,860)	140,034
Interest rate lock commitments to loans held for sale	(6,955)	(7,815)
Mortgage servicing rights relating to delinquent loans to Agency	295	221
Ending balance	3,721,981	3,875,551
Changes in fair value recognized during the quarter relating to assets	(64,371)	155,530
Recurring [Member] \| Credit Risk Transfer Strips [Member]
Assets:
Beginning balance	(5,999)	(4,060)
Purchases and issuances	0	0
Repayments and sales	(8,424)	(9,777)
Accrual of unearned discount	0	0
Amounts received pursuant to sales of loans	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0
Other factors	10,361	2,048
Total	10,361	2,048
Interest rate lock commitments to loans held for sale	0	0
Mortgage servicing rights relating to delinquent loans to Agency	0	0
Ending balance	(4,062)	(15,885)
Changes in fair value recognized during the quarter relating to assets	1,806	11,825
Recurring [Member] \| Credit Risk Transfer Derivatives [Member]
Assets:
Beginning balance	32,659	29,377
Purchases and issuances	0	0
Repayments and sales	(2,617)	(2,883)
Accrual of unearned discount	0	0
Amounts received pursuant to sales of loans	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0
Other factors	132	1,980
Total	132	1,980
Interest rate lock commitments to loans held for sale	0	0
Mortgage servicing rights relating to delinquent loans to Agency	0	0
Ending balance	30,174	28,474
Changes in fair value recognized during the quarter relating to assets	(2,416)	823
Recurring [Member] \| Loans At Fair Value [Member]
Assets:
Beginning balance		1,866
Purchases and issuances		0
Repayments and sales		(20)
Accrual of unearned discount		0
Amounts received pursuant to sales of loans		0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk		0
Other factors		(31)
Total		(31)
Interest rate lock commitments to loans held for sale		0
Mortgage servicing rights relating to delinquent loans to Agency		0
Ending balance		1,815
Changes in fair value recognized during the quarter relating to assets		(31)
Recurring [Member] \| Loans Held for Investment [Member]
Assets:
Beginning balance	1,705
Purchases and issuances	0
Repayments and sales	(16)
Accrual of unearned discount	0
Amounts received pursuant to sales of loans	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0
Other factors	(39)
Total	(39)
Interest rate lock commitments to loans held for sale	0
Mortgage servicing rights relating to delinquent loans to Agency	0
Ending balance	1,650
Changes in fair value recognized during the quarter relating to assets	(39)
Recurring [Member] \| Mortgage servicing rights [Member]
Assets:
Beginning balance	3,644,702	3,867,394
Purchases and issuances	0	0
Repayments and sales	0	0
Accrual of unearned discount	0	0
Amounts received pursuant to sales of loans	40,281	47,009
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0
Other factors	(61,299)	(144,590)
Total	(61,299)	(144,590)
Interest rate lock commitments to loans held for sale	0	0
Mortgage servicing rights relating to delinquent loans to Agency	295	221
Ending balance	3,623,979	3,770,034
Changes in fair value recognized during the quarter relating to assets	(61,299)	(144,590)
Recurring [Member] \| Loans acquired for sale [Member]
Assets:
Beginning balance		7,971
Purchases and issuances		28
Repayments and sales		(2,678)
Accrual of unearned discount		0
Amounts received pursuant to sales of loans		0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk		0
Other factors		(130)
Total		(130)
Interest rate lock commitments to loans held for sale		0
Mortgage servicing rights relating to delinquent loans to Agency		0
Ending balance		5,451
Changes in fair value recognized during the quarter relating to assets		(14)
Recurring [Member] \| Loans Held For Sale [Member]
Assets:
Beginning balance	3,581
Purchases and issuances	3,601
Repayments and sales	(4,950)
Accrual of unearned discount	0
Amounts received pursuant to sales of loans	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0
Other factors	(148)
Total	(148)
Interest rate lock commitments to loans held for sale	0
Mortgage servicing rights relating to delinquent loans to Agency	0
Ending balance	2,084
Changes in fair value recognized during the quarter relating to assets	(219)
Recurring [Member] \| Interest Rate Lock Commitments with PFSI [Member]
Assets:
Beginning balance	2,348	444
Purchases and issuances	5,270	4,599
Repayments and sales	0	0
Accrual of unearned discount	0	0
Amounts received pursuant to sales of loans	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0
Other factors	(3,936)	(7,391)
Total	(3,936)	(7,391)
Interest rate lock commitments to loans held for sale	(6,955)	(7,815)
Mortgage servicing rights relating to delinquent loans to Agency	0	0
Ending balance	(3,273)	4,619
Changes in fair value recognized during the quarter relating to assets	(3,273)	4,619
Recurring [Member] \| Interest-only security payable [Member]
Liabilities:
Beginning balance	37,650	34,222
Change in instrument-specific credit risk\Other factors	(3,418)	1,732
Ending balance	34,232	35,954
Change in fair value recognized during the quarter relating to liability	(3,418)	1,732
Recurring [Member] \| Interest-only security payable [Member] \| Credit Risk [Member]
Liabilities:
Change in instrument-specific credit risk\Other factors	0	0
Recurring [Member] \| Interest-only security payable [Member] \| Other Factors [Member]
Liabilities:
Change in instrument-specific credit risk\Other factors	(3,418)	1,732
Recurring [Member] \| Interest-Only Stripped Mortgage-Backed Securities [Member]
Assets:
Beginning balance	72,502	86,260
Purchases and issuances	0	0
Repayments and sales	(4,107)	(4,636)
Accrual of unearned discount	1,965	2,285
Amounts received pursuant to sales of loans	0	0
Changes in fair value included in income arising from:
Changes in instrument-specific credit risk	0	0
Other factors	1,069	2,866
Total	1,069	2,866
Interest rate lock commitments to loans held for sale	0	0
Mortgage servicing rights relating to delinquent loans to Agency	0	0
Ending balance	71,429	81,043
Changes in fair value recognized during the quarter relating to assets	$ 1,069	$ 2,866

Fair value measurement with unobservable inputs reconciliation recurring basis accrual of unearned discount.

No definition available.

Name:	pmt_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAccrualOfUnearnedDiscount
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis Asset Purchases And Issuances

+ References

No definition available.

+ Details

Name:	pmt_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesAndIssuances
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value measurement with unobservable inputs reconciliation recurring basis asset sales and settlements.

+ References

No definition available.

+ Details

Name:	pmt_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSalesAndSettlements
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Changes in fair value of mortgage loans attributable to changes in inputs other than credit.

+ References

No definition available.

+ Details

Name:	pmt_FairValueOptionNonCreditRiskGainsLossesOnAssets
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The value of new servicing assets, subsequently measured at fair value, acquired or created during the current period from transfers of financial assets.

+ References

No definition available.

+ Details

Name:	pmt_ServicingAssetAtFairValueAdditionsFromLoanSales
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Transfer of interest rate lock commitments to loans held for sale.

+ References

No definition available.

+ Details

Name:	pmt_TransferOfInterestRateLockCommitmentsToLoansHeldForSale
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Transfer of mortgage servicing rights relating to delinquent loans to agency.

+ References

No definition available.

+ Details

Name:	pmt_TransferOfMortgageServicingRightsRelatingToDelinquentLoansToAgency
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_FairValueAdjustmentDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 101
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-101

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 102
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-102

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 101
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-101

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 102
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-102

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 101
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-101

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents the estimated amount of gains or losses included in earnings during the period attributable to changes in instrument-specific credit risk arising from loans and other receivables held as assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-30

+ Details

Name:	us-gaap_FairValueOptionCreditRiskGainsLossesOnAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_LiabilitiesFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_InterestRateLockCommitmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditDerivativesByContractTypeAxis=pmt_CreditRiskTransferStripsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditDerivativesByContractTypeAxis=pmt_CreditRiskTransferDerivativesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=pmt_LoansAtFairValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=pmt_LoansHeldForInvestmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=pmt_MortgageServicingRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=pmt_LoansAcquiredForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=pmt_LoansHeldForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=pmt_InterestOnlySecurityPayableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ManagingRisksInherentInServicingAssetsAndServicingLiabilitiesByTypeOfRiskAxis=us-gaap_CreditRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ManagingRisksInherentInServicingAssetsAndServicingLiabilitiesByTypeOfRiskAxis=pmt_OtherRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=pmt_InterestOnlyStrippedMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: