Short-Term Borrowings - Assets Sold Under Agreement to Repurchase (Details) - USD ($) $ in Thousands			12 Months Ended
	Apr. 28, 2021	Dec. 19, 2016	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Carrying value:
Net amounts of liabilities presented in the consolidated balance sheet			$ 3,004,690
Total loans sold under agreements to repurchase			3,001,283	$ 7,292,735
Loans held for sale			3,509,300	9,742,483
Servicing advances, net			696,753	702,160
Mortgage servicing rights, at fair value			5,953,621	3,878,078
Other Assets			417,907	616,616
Margin deposits placed with counterparties			55,968	100,482
PennyMac Holdings, L L C Repurchase Agreement
Carrying value:
Maximum principal balance of VFN		$ 2,000,000
Note Payable
During the period:
Average balance of assets sold under agreements to repurchase			1,584,383	1,300,000	$ 1,300,000
Carrying value:
Amortization of debt issuance costs			2,500	2,200	1,800
Loan Repo Facility
During the period:
Average balance of assets sold under agreements to repurchase			$ 2,580,513	$ 6,911,843	$ 3,348,928
Weighted-average interest rate (as a percent)			3.59%	2.09%	2.91%
Total interest expense			$ 105,459	$ 164,132	$ 112,778
Maximum daily amount outstanding			7,289,147	10,969,029	9,663,995
Carrying value:
Unpaid principal balance under committed facilities			2,476,073	5,079,581
Unpaid principal balance under uncommitted facilities			528,617	2,217,779
Net amounts of liabilities presented in the consolidated balance sheet			3,004,690	7,297,360
Unamortized debt issuance costs and premiums			(3,407)	(4,625)
Total loans sold under agreements to repurchase			$ 3,001,283	$ 7,292,735
Weighted average interest rate (as a percent)			6.00%	1.83%
Available borrowing capacity committed			$ 1,078,927	$ 285,419
Available borrowing capacity uncommitted			5,391,383	8,417,221
Available borrowing capacity			6,470,310	8,702,640
Amortization of debt issuance costs			12,900	19,400	$ 15,300
FMSR VFN Repurchase Agreement
Carrying value:
Maximum principal balance of VFN	$ 250,000
Maximum principal balance of VFN	$ 1,000,000
Asset Pledged as Collateral without Right
Carrying value:
Loans held for sale			3,442,847	9,135,577
Servicing advances, net			$ 381,379	$ 232,107
Assets, Pledging Purpose [Extensible Enumeration]			Notes Payable	Notes Payable
Mortgage servicing rights, at fair value			$ 5,897,613	$ 3,856,791
Other Assets			$ 12,277	$ 45,294
Asset Pledged as Collateral without Right | Mortgage servicing rights
Carrying value:
Assets, Pledging Purpose [Extensible Enumeration]			Notes Payable	Notes Payable
Asset Pledged as Collateral without Right | Mortgage servicing rights
Carrying value:
Assets, Pledging Purpose [Extensible Enumeration]			Notes Payable	Notes Payable
Asset Pledged as Collateral without Right | Note Payable | Mortgage servicing rights
Carrying value:
Mortgage servicing rights, at fair value			$ 5,897,613	$ 3,856,791
Asset Pledged as Collateral without Right | Note Payable | Servicing advances
Carrying value:
Servicing advances, net			381,379	232,107
Asset Pledged as Collateral without Right | Loan Repo Facility | Servicing advances
Carrying value:
Servicing advances, net			381,379	232,107
Asset Pledged as Collateral without Right | Loan Repo Facility | Mortgage servicing rights
Carrying value:
Mortgage servicing rights, at fair value			5,339,513	3,552,812
Asset Pledged as Collateral without Right | Mortgage loans held for sale | Loan Repo Facility | Loans held for sale
Carrying value:
Loans held for sale			3,139,870	8,629,861
Asset Pledged as Collateral without Right | Deposits.
Carrying value:
Other Assets			12,277	36,632
Asset Pledged as Collateral without Right | Deposits. | Loan Repo Facility | Deposits
Carrying value:
Other Assets			$ 12,277	$ 36,632