Mortgage Servicing Rights and Mortgage Servicing Liabilities - Servicing, Late, Ancillary and Other Fees Relating to MSRs (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Contractual servicing fees	$ 199,178	$ 180,753	$ 397,831	$ 347,543
Other fees:
Other	28,543	26,008	57,298	48,025
Mortgage servicing rights
Contractual servicing fees	199,178	180,753	397,831	347,543
Other fees:
Late charges	8,490	9,015	21,103	18,827
Other	5,971	2,612	10,821	4,273
Bank Servicing Fees	$ 213,639	$ 192,380	$ 429,755	$ 370,643

N/A

No definition available.

Name:	pfsi_LateFeesAndAncillaryFeesEarnedInExchangeForServicingFinancialAssetsAbstract
Namespace Prefix:	pfsi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

All amounts that are due to the servicer of a financial asset, excluding contractually specified servicing fees and late fees.

+ 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=116651436&loc=d3e122596-111746

+ Details

Name:	us-gaap_AncillaryFeeIncomeGeneratedByServicingFinancialAssetsAmount
Namespace Prefix:	us-gaap_
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

+ Details

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

- Definition

Amount of contractually specified servicing fee, late fee, and ancillary fee recognized as income for servicing asset and servicing liability.

+ References

+ Details

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

- Definition

All amounts that are due to the servicer of a financial asset as a result of the debt holder not meeting the monthly payment terms.

+ References

+ Details

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

- Details

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