Carrying value.

No definition available.

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

- Definition

Represents the weighted average balance of exchangeable notes outstanding during the period.

+ References

No definition available.

+ Details

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

- Definition

Unamortized debt issuance costs.

+ References

No definition available.

+ Details

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

- Definition

Unsecured Debt balance include Exchangeable Senior Notes and 2023 Senior Notes.

+ References

No definition available.

+ Details

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

- Definition

Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

+ 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

+ Details

Name:	us-gaap_ConvertibleDebt
Namespace Prefix:	us-gaap_
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

- 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

- Details

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

- Details

Name:	dei_LegalEntityAxis=pmt_NonAffiliatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Long-Term Debt - Summary of Financial Information Relating to Unsecured Senior Notes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2030	Sep. 30, 2029	Sep. 30, 2028	Sep. 30, 2027	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2023
Carrying value:
Exchangeable senior notes	$ 814,915		$ 814,915								$ 600,458
Convertible Debt [Member]
Carrying value:
Unamortized debt issuance costs	(10,085)		(10,085)								(8,042)
Convertible Debt [Member] \| Nonaffiliates [Member]
Short Term Debt [Line Items]
Average balance	$ 825,000	$ 553,338	$ 710,496	$ 549,063
Weighted average interest rate	6.45%	5.56%	6.16%	5.60%
Interest expense	$ 14,571	$ 8,541	$ 35,884	$ 25,316
Exchangeable Senior Notes and 2023 Senior Notes [Member]
Carrying value:
Unpaid principal balance	$ 825,000		$ 825,000		$ 0	$ 216,500	$ 53,500	$ 0	$ 345,000	$ 210,000	$ 608,500