Long-Term Debt - Summary of Financial Information Relating to Note Payable Secured by Credit Risk Transfer and Mortgage Servicing Assets (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Carrying value:
Balance	$ 2,396,545		$ 2,258,128
Freddie Mac Mortgage Servicing Rights Financing [Member]
Carrying value:
Balance	2,396,545		2,258,128
Carrying value of notes	2,401,600		2,261,846
Assets securing notes payable:
Mortgage servicing rights at fair value	3,560,828		3,582,211
Servicing advances	28,675		33,777
Deposits securing CRT arrangements	815,983		832,640
Notes Payable [Member] \| Freddie Mac Mortgage Servicing Rights Financing [Member]
Carrying value:
Unamortized debt issuance costs	$ (5,055)		$ (3,718)
Weighted average interest rate	6.85%		6.91%
Assets securing notes payable:
Derivative assets	$ 21,005		$ 20,037
Notes Payable [Member] \| Freddie Mac MSR Financing
Short Term Debt [Line Items]
Average balance	$ 2,316,141	$ 2,830,048
Weighted-average interest rate	6.92%	7.59%
Total interest expense	$ 41,260	$ 55,255
Credit Risk Transfer Arrangement Financing [Member] \| Freddie Mac Mortgage Servicing Rights Financing [Member]
Carrying value:
Carrying value of notes	596,965		608,903
Freddie Mac Credit Agreements [Member] \| Fannie Mae Mortgage Servicing Rights Financing [Member]
Carrying value:
Carrying value of notes	725,000		725,000
Freddie Mac Credit Agreements [Member] \| Freddie Mac Mortgage Servicing Rights And Servicing Advance Receivables Financing [Member]
Carrying value:
Carrying value of notes	$ 1,079,635		$ 927,943

Carrying value.

No definition available.

Name:	pmt_CarryingValueAbstract
Namespace Prefix:	pmt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Deposits securing credit risk transfers pledged to creditors.

+ References

No definition available.

+ Details

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

- Definition

Derivative assets pledged to creditors.

+ References

No definition available.

+ Details

Name:	pmt_DerivativeAssetsPledgedToCreditors
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Long term debt average balance during period.

+ References

No definition available.

+ Details

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

- Definition

Mortgage servicing rights, secured notes payable.

+ References

No definition available.

+ Details

Name:	pmt_MortgageServicingRightsSecuredNotesPayable
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Notes payable gross.

+ References

No definition available.

+ Details

Name:	pmt_NotesPayableGross
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Servicing advances secured notes payable

+ References

No definition available.

+ Details

Name:	pmt_ServicingAdvancesSecuredNotesPayable
Namespace Prefix:	pmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Aggregate amount of interest paid or due on all long-term debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph a
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph b
-Subparagraph (1)
-Publisher SEC

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(8))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

+ Details

Name:	us-gaap_InterestExpenseLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Weighted average interest rate of long-term debt outstanding calculated over time.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtWeightedAverageInterestRateOverTime
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

+ Details

Name:	us-gaap_LongtermDebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(17))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_TypeOfArrangementAxis=pmt_FreddieMacMortgageServicingRightsFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=pmt_NotesPayableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=pmt_FreddieMacMSRFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=pmt_CreditRiskTransferArrangementFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=pmt_FreddieMacCreditAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=pmt_FannieMaeMortgageServicingRightsFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=pmt_FreddieMacMortgageServicingRightsAndServicingAdvanceReceivablesFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: