Segments (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segments and Related Information
Number of segments | segment			3
Revenues:
Net gains on loans held for sale at fair value	$ 168,694	$ 626,754	$ 689,720	$ 1,963,743
Loan origination fees	34,037	94,581	141,840	295,909
Fulfillment fees from PennyMac Mortgage Investment Trust	18,407	43,922	55,807	158,777
Net loan servicing fees	243,742	33,630	768,498	88,221
Net interest income (expense):
Interest income	82,994	68,312	186,740	231,190
Interest expense, before non-segment activities	82,965	90,711	231,399	300,855
Net interest expense, before non-segment activities	29	(22,399)	(44,659)	(69,665)
Management fees from PennyMac Mortgage Investment Trust	7,731	8,520	23,758	28,882
Other	3,650	1,604	10,345	7,683
Total net revenues, before non-segment activities	476,290	786,612	1,645,309	2,473,550
Expenses	290,818	447,063	1,047,791	1,348,478
Income before provision for income taxes	185,472	339,549	597,518	1,125,072
Assets:
Segment assets at quarter end	16,361,811	19,745,138	16,361,811	19,745,138	$ 18,776,612
PennyMac Mortgage Investment Trust
Revenues:
Net gains on loans held for sale at fair value	(1,648)	(12,976)	(16,052)	(38,772)
Net interest income (expense):
Interest income				387
Operating segment
Assets:
Segment assets at quarter end	16,361,811	19,745,138	16,361,811	19,745,138
Operating segment | Investment management
Net interest income (expense):
Interest expense, before non-segment activities		2		8
Net interest expense, before non-segment activities		(2)		(8)
Management fees from PennyMac Mortgage Investment Trust	7,731	8,520	23,758	28,882
Other	2,620	1,238	6,431	3,968
Total net revenues, before non-segment activities	10,351	9,756	30,189	32,842
Expenses	8,734	8,727	28,228	26,295
Income before provision for income taxes	1,617	1,029	1,961	6,547
Assets:
Segment assets at quarter end	26,988	20,727	26,988	20,727
Operating segment | Mortgage banking
Revenues:
Net gains on loans held for sale at fair value	168,694	626,754	689,720	1,963,743
Loan origination fees	34,037	94,581	141,840	295,909
Fulfillment fees from PennyMac Mortgage Investment Trust	18,407	43,922	55,807	158,777
Net loan servicing fees	243,742	33,630	768,498	88,221
Net interest income (expense):
Interest income	82,994	68,312	186,740	231,190
Interest expense, before non-segment activities	82,965	90,709	231,399	300,847
Net interest expense, before non-segment activities	29	(22,397)	(44,659)	(69,657)
Other	1,030	366	3,914	3,715
Total net revenues, before non-segment activities	465,939	776,856	1,615,120	2,440,708
Expenses	282,084	438,336	1,019,563	1,322,183
Income before provision for income taxes	183,855	338,520	595,557	1,118,525
Assets:
Segment assets at quarter end	16,334,823	19,724,411	16,334,823	19,724,411
Operating segment | Mortgage banking Production
Revenues:
Net gains on loans held for sale at fair value	140,683	496,568	515,188	1,431,824
Loan origination fees	34,037	94,581	141,840	295,909
Fulfillment fees from PennyMac Mortgage Investment Trust	18,407	43,922	55,807	158,777
Net interest income (expense):
Interest income	30,825	33,307	90,145	94,668
Interest expense, before non-segment activities	24,970	28,570	71,236	103,555
Net interest expense, before non-segment activities	5,855	4,737	18,909	(8,887)
Other	474	218	1,842	1,445
Total net revenues, before non-segment activities	199,456	640,026	733,586	1,879,068
Expenses	160,884	309,460	676,090	941,165
Income before provision for income taxes	38,572	330,566	57,496	937,903
Assets:
Segment assets at quarter end	4,708,512	7,926,709	4,708,512	7,926,709
Operating segment | Mortgage banking Servicing
Revenues:
Net gains on loans held for sale at fair value	28,011	130,186	174,532	531,919
Net loan servicing fees	243,742	33,630	768,498	88,221
Net interest income (expense):
Interest income	52,169	35,005	96,595	136,522
Interest expense, before non-segment activities	57,995	62,139	160,163	197,292
Net interest expense, before non-segment activities	(5,826)	(27,134)	(63,568)	(60,770)
Other	556	148	2,072	2,270
Total net revenues, before non-segment activities	266,483	136,830	881,534	561,640
Expenses	121,200	128,876	343,473	381,018
Income before provision for income taxes	145,283	7,954	538,061	180,622
Assets:
Segment assets at quarter end	$ 11,626,311	$ 11,797,702	$ 11,626,311	$ 11,797,702