Segments (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) segment	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Segments and Related Information
Number of segments | segment			3
Revenues:
Net gains on loans held for sale at fair value	$ 256,819	$ 151,374	$ 595,324	$ 397,178
Loan origination fees	49,430	37,701	127,876	108,059
Fulfillment fees from PennyMac Mortgage Investment Trust	11,492	5,531	19,935	22,895
Net loan servicing fees	75,830	185,374	344,388	480,289
Net interest income (expense):
Interest income	225,470	166,552	582,707	467,982
Interest expense	217,597	156,863	591,237	467,276
Net interest expense, before non-segment activities	7,873	9,689	(8,530)	706
Management fees from PennyMac Mortgage Investment Trust	7,153	7,175	21,474	21,510
Other	3,237	3,464	23,154	9,080
Total net revenues	411,834	400,308	1,123,621	1,039,717
Expenses	317,909	273,511	851,959	801,856
Income before provision for income taxes	93,925	126,797	271,662	237,861
Assets:
Segment assets at year end	22,871,538	18,949,314	22,871,538	18,949,314	$ 18,844,563
Operating segment
Assets:
Segment assets at year end	22,871,538	18,949,314	22,871,538	18,949,314
Operating segment | Investment management
Net interest income (expense):
Interest income	99		262
Net interest expense, before non-segment activities	99		262
Management fees from PennyMac Mortgage Investment Trust	7,153	7,175	21,474	21,510
Other	2,100	1,604	6,344	6,037
Total net revenues	9,352	8,779	28,080	27,547
Expenses	8,658	8,379	20,296	24,849
Income before provision for income taxes	694	400	7,784	2,698
Assets:
Segment assets at year end	14,469	22,350	14,469	22,350
Operating segment | Mortgage banking
Revenues:
Net gains on loans held for sale at fair value	256,819	151,374	595,324	397,178
Loan origination fees	49,430	37,701	127,876	108,059
Fulfillment fees from PennyMac Mortgage Investment Trust	11,492	5,531	19,935	22,895
Net loan servicing fees	75,830	185,374	344,388	480,289
Net interest income (expense):
Interest income	225,371	166,552	582,445	467,982
Interest expense	217,597	156,863	591,237	467,276
Net interest expense, before non-segment activities	7,774	9,689	(8,792)	706
Other	1,137	1,860	16,810	3,043
Total net revenues	402,482	391,529	1,095,541	1,012,170
Expenses	309,251	265,132	831,663	777,007
Income before provision for income taxes	93,231	126,397	263,878	235,163
Assets:
Segment assets at year end	22,857,069	18,926,964	22,857,069	18,926,964
Operating segment | Mortgage banking Production
Revenues:
Net gains on loans held for sale at fair value	235,902	127,821	531,650	328,796
Loan origination fees	49,430	37,701	127,876	108,059
Fulfillment fees from PennyMac Mortgage Investment Trust	11,492	5,531	19,935	22,895
Net interest income (expense):
Interest income	79,386	62,150	227,930	194,566
Interest expense	81,496	59,614	226,768	189,691
Net interest expense, before non-segment activities	(2,110)	2,536	1,162	4,875
Other	625	823	1,952	1,925
Total net revenues	295,339	174,412	682,575	466,550
Expenses	187,486	149,219	497,551	436,582
Income before provision for income taxes	107,853	25,193	185,024	29,968
Assets:
Segment assets at year end	6,846,311	5,485,039	6,846,311	5,485,039
Operating segment | Mortgage banking Servicing
Revenues:
Net gains on loans held for sale at fair value	20,917	23,553	63,674	68,382
Net loan servicing fees	75,830	185,374	344,388	480,289
Net interest income (expense):
Interest income	145,985	104,402	354,515	273,416
Interest expense	136,101	97,249	364,469	277,585
Net interest expense, before non-segment activities	9,884	7,153	(9,954)	(4,169)
Other	512	1,037	14,858	1,118
Total net revenues	107,143	217,117	412,966	545,620
Expenses	121,765	115,913	334,112	340,425
Income before provision for income taxes	(14,622)	101,204	78,854	205,195
Assets:
Segment assets at year end	$ 16,010,758	$ 13,441,925	$ 16,010,758	$ 13,441,925