The activity-based fee on a related party transaction, due to the Company as a result of a deed-in-lieu of foreclosure.

No definition available.

Name:	pfsi_RelatedPartyTransactionActivityBasedFeeForDistressedWholeMortgageLoansDeedInLieuOfForeclosure
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The activity-based fee percent on a related party transaction, due to the Company as a result of a liquidation.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionActivityBasedFeePercentForDistressedWholeMortgageLoansLiquidation
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The activity-based fee percent on a related party transaction, due to the Company as a result of a streamline modification.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionActivityBasedFeePercentForDistressedWholeMortgageLoansStreamlineModification
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The renewal period that automatically renews at expiration, unless terminated earlier in accordance with the terms of the agreement, for the related party agreement.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionAgreementTermAutomaticRenewalPeriod
Namespace Prefix:	pfsi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the base servicing fee per month for real estate in settlement of loans.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionBaseServicingFeePerMonthForRealEstateInSettlementOfLoans
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Related Party Transaction, Base Servicing Fee Per Month for Subserviced Adjustable Rate Loans

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionBaseServicingFeePerMonthForSubservicedAdjustableRateLoans
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Related Party Transaction, Base Servicing Fee Per Month for Subserviced Fixed Rate Loans

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionBaseServicingFeePerMonthForSubservicedFixedRateLoans
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The length of the earnable period during which only a maximum number of liquidation fees, reperformance fees, or modification fees can be earned for a related party transaction.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionLiquidationReperformanceOrModificationFeesEarnablePeriod
Namespace Prefix:	pfsi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum number of liquidation fees, reperformance fees, or modification fees that can be earned during a given earnable period, as part of a related party transaction.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionMaximumNumberOfLiquidationReperformanceOrModificationFeesToBeEarnedInEarnablePeriod
Namespace Prefix:	pfsi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the property management fee for real estate in settlement of loans, as a percentage of gross rental income, when the Company provides property management services directly.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionPropertyManagementFeeForRealEstateInSettlementOfLoansPercentageOfGrossRentalIncome
Namespace Prefix:	pfsi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the renewal fee, per lease renewal, on REO property.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionRenewalFeePerLeaseRenewal
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the rental fee per month per REO for real estate in settlement of loans that when REO properties are leased and receive rent.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionRentalFeePerMonthForRealEstateInSettlementOfLoans
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The rate is for loans where borrower has declared bankruptcy.

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionServicingFeePerMonthForCurrentLoans
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Related Party Transaction, Servicing Fee Per Month for Severely Delinquent Loans

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionServicingFeePerMonthForSeverelyDelinquentLoans
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Related Party Transaction, Supplemental Fee Per Month for Each Distressed Whole Loan

+ References

No definition available.

+ Details

Name:	pfsi_RelatedPartyTransactionSupplementalFeePerMonthForEachDistressedWholeLoan
Namespace Prefix:	pfsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

All amounts that, per contract, are due to the servicer in exchange for servicing the financial asset and would no longer be received by a servicer if the beneficial owners of the serviced assets (or their trustees or agents) were to exercise their actual or potential authority under the contract to shift the servicing to another servicer. Depending on the servicing contract, those fees may include some or all of the difference between the interest rate collected on the asset being serviced and the rate to be paid to the beneficial owners of the asset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122596-111746

+ Details

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

- Definition

The amount of revenue derived from managing real estate properties.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyManagementFeeRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=pfsi_MortgageLoanServicingAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=pfsi_PennyMacMortgageInvestmentTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_OtherIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Transactions with Affiliates - Mortgage Loan Servicing (Details)		3 Months Ended
	Sep. 12, 2016 USD ($) item	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Summary of mortgage loan servicing fees earned
Loan servicing fees		$ 166,790,000	$ 135,483,000
Mortgage Loan Servicing Agreement
Transactions with Affiliates
Base servicing fees per month for REO	$ 75
Rental fee per month per REO	30
Renewal fee, per lease renewal, on REO property	$ 100
Property management fees on REOs, as a percent of gross rental income	9.00%
Base servicing fees per month for fixed-rate non-distressed loans subserviced	$ 7.50
Base servicing fees per month for adjustable rate non-distressed loans subserviced	8.50
Supplemental fee per month for each distressed whole loan	25
Activity-based fee, percent, due to a streamline modification	750
Activity-based fee, percent, due to a liquidation	1,750
Activity-based fee due to a deed-in-lieu of foreclosure	$ 500
Maximum number of liquidation, reperformance, or modification fees that can be earned during earnable period \| item	1
Liquidation, reperformance, or modification fees earnable period	18 months
Related party transaction, automatic renewal period	18 months
Minimum \| Mortgage Loan Servicing Agreement
Transactions with Affiliates
Servicing fees amount per month for current loans	$ 30
Maximum \| Mortgage Loan Servicing Agreement
Transactions with Affiliates
Servicing fees amount per month for severely delinquent loans	$ 85
PMT
Summary of mortgage loan servicing fees earned
Loan servicing fees		10,570,000	11,019,000
PMT \| Mortgage loans acquired for sale at fair value
Summary of mortgage loan servicing fees earned
Loan servicing fees		239,000	178,000
PMT \| Mortgage loans at fair value
Summary of mortgage loan servicing fees earned
Loan servicing fees		463,000	3,085,000
PMT \| Mortgage servicing rights
Summary of mortgage loan servicing fees earned
Loan servicing fees		9,868,000	7,756,000
PMT \| Other income.
Summary of mortgage loan servicing fees earned
Property management fees		$ 123,000	$ 99,000