Segments (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) segment	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Segments and Related Information
Number of operating segments | segment			2
Number of reportable segments | segment			2
Revenues:
Net gains on loans held for sale at fair value	$ 234,659	$ 176,064	$ 455,696	$ 338,505
Loan origination fees	59,091	42,075	105,702	78,446
Fulfillment fees from PennyMac Mortgage Investment Trust	5,814	4,427	11,104	8,443
Net loan servicing fees	150,395	167,604	314,681	268,558
Management fees	6,869	7,133	13,881	14,321
Net interest income (expense):
Interest income	221,929	200,811	411,800	357,237
Interest expense	239,577	207,871	447,659	373,640
Net interest income (expense)	(17,648)	(7,060)	(35,859)	(16,403)
Other	5,550	15,884	10,428	19,917
Total net revenues	444,730	406,127	875,633	711,787
Expenses:
Compensation	187,541	141,956	369,529	288,332
Loan origination	68,836	40,270	112,932	70,838
Technology	42,257	35,690	82,454	71,657
Servicing	28,286	22,920	50,161	39,024
Professional services	8,380	9,404	17,417	18,666
Occupancy and equipment	8,379	7,893	16,761	16,569
Marketing and advertising	12,389	5,445	21,821	9,116
Other	12,220	8,695	23,920	19,848
Total expenses	368,288	272,273	694,995	534,050
Income before (benefit from) provision for income taxes	76,442	133,854	180,638	177,737
Acquisition of:
Segment assets at end of quarter	24,221,904	21,577,565	24,221,904	21,577,565	$ 26,086,887
Capitalized software	9,146	4,797	16,283	8,661
Furniture, fixtures, equipment and building improvements	1,305	401	1,676	1,319
Amortization of capitalized software	12,813	12,242	24,794	24,423
Depreciation and amortization of furniture, fixtures, equipment and building improvements			28,627	28,404
Furniture, Fixtures, Equipment and Building Improvements
Acquisition of:
Depreciation and amortization of furniture, fixtures, equipment and building improvements	1,918	1,998	3,833	3,981
Operating segment
Revenues:
Net gains on loans held for sale at fair value	234,659	176,064	455,696	338,505
Loan origination fees	59,091	42,075	105,702	78,446
Fulfillment fees from PennyMac Mortgage Investment Trust	5,814	4,427	11,104	8,443
Net loan servicing fees	150,395	167,604	314,681	268,558
Net interest income (expense):
Interest income	221,328	200,351	410,750	356,263
Interest expense	239,577	207,871	447,659	373,640
Net interest income (expense)	(18,249)	(7,520)	(36,909)	(17,377)
Other	1,270	349	1,228	972
Total net revenues	432,980	382,999	851,502	677,547
Expenses:
Compensation	155,740	120,360	307,579	242,953
Loan origination	68,836	40,270	112,932	70,838
Technology	37,346	32,751	72,831	65,282
Servicing	28,286	22,920	50,161	39,024
Professional services	5,343	4,020	10,158	7,430
Occupancy and equipment	6,840	6,507	13,697	13,550
Marketing and advertising	10,660	4,814	19,056	8,439
Other	7,989	5,486	15,204	11,828
Total expenses	321,040	237,128	601,618	459,344
Income before (benefit from) provision for income taxes	111,940	145,871	249,884	218,203
Acquisition of:
Segment assets at end of quarter	24,155,522	21,489,060	24,155,522	21,489,060
Capitalized software	9,146	4,659	16,283	8,410
Furniture, fixtures, equipment and building improvements	957	373	1,173	1,234
Amortization of capitalized software	12,710	11,785	24,597	23,474
Operating segment | Furniture, Fixtures, Equipment and Building Improvements
Acquisition of:
Depreciation and amortization of furniture, fixtures, equipment and building improvements	1,628	1,666	3,241	3,322
Operating segment | Mortgage banking Production
Revenues:
Net gains on loans held for sale at fair value	203,961	154,317	391,106	295,748
Loan origination fees	59,091	42,075	105,702	78,446
Fulfillment fees from PennyMac Mortgage Investment Trust	5,814	4,427	11,104	8,443
Net interest income (expense):
Interest income	104,205	84,645	189,493	148,016
Interest expense	93,622	83,376	170,148	145,272
Net interest income (expense)	10,583	1,269	19,345	2,744
Other	132	155	263	271
Total net revenues	279,581	202,243	527,520	385,652
Expenses:
Compensation	104,456	70,900	203,325	141,093
Loan origination	68,836	40,270	112,932	70,838
Technology	27,841	22,977	52,941	45,745
Professional services	3,545	2,422	6,679	4,484
Occupancy and equipment	4,109	3,754	8,237	7,892
Marketing and advertising	10,276	4,793	18,299	8,389
Other	2,730	1,958	5,376	3,364
Total expenses	221,793	147,074	407,789	281,805
Income before (benefit from) provision for income taxes	57,788	55,169	119,731	103,847
Acquisition of:
Segment assets at end of quarter	7,161,516	6,454,411	7,161,516	6,454,411
Capitalized software	6,970	3,884	12,379	7,325
Furniture, fixtures, equipment and building improvements	617	109	804	361
Amortization of capitalized software	11,175	9,772	21,396	19,258
Operating segment | Mortgage banking Production | Furniture, Fixtures, Equipment and Building Improvements
Acquisition of:
Depreciation and amortization of furniture, fixtures, equipment and building improvements	976	925	1,944	1,884
Operating segment | Mortgage banking Servicing
Revenues:
Net gains on loans held for sale at fair value	30,698	21,747	64,590	42,757
Net loan servicing fees	150,395	167,604	314,681	268,558
Net interest income (expense):
Interest income	117,123	115,706	221,257	208,247
Interest expense	145,955	124,495	277,511	228,368
Net interest income (expense)	(28,832)	(8,789)	(56,254)	(20,121)
Other	1,138	194	965	701
Total net revenues	153,399	180,756	323,982	291,895
Expenses:
Compensation	51,284	49,460	104,254	101,860
Technology	9,505	9,774	19,890	19,537
Servicing	28,286	22,920	50,161	39,024
Professional services	1,798	1,598	3,479	2,946
Occupancy and equipment	2,731	2,753	5,460	5,658
Marketing and advertising	384	21	757	50
Other	5,259	3,528	9,828	8,464
Total expenses	99,247	90,054	193,829	177,539
Income before (benefit from) provision for income taxes	54,152	90,702	130,153	114,356
Acquisition of:
Segment assets at end of quarter	16,994,006	15,034,649	16,994,006	15,034,649
Capitalized software	2,176	775	3,904	1,085
Furniture, fixtures, equipment and building improvements	340	264	369	873
Amortization of capitalized software	1,535	2,013	3,201	4,216
Operating segment | Mortgage banking Servicing | Furniture, Fixtures, Equipment and Building Improvements
Acquisition of:
Depreciation and amortization of furniture, fixtures, equipment and building improvements	652	741	1,297	1,438
Corporate and other
Revenues:
Management fees	6,869	7,133	13,881	14,321
Net interest income (expense):
Interest income	601	460	1,050	974
Net interest income (expense)	601	460	1,050	974
Other	4,280	15,535	9,200	18,945
Total net revenues	11,750	23,128	24,131	34,240
Expenses:
Compensation	31,801	21,596	61,950	45,379
Technology	4,911	2,939	9,623	6,375
Professional services	3,037	5,384	7,259	11,236
Occupancy and equipment	1,539	1,386	3,064	3,019
Marketing and advertising	1,729	631	2,765	677
Other	4,231	3,209	8,716	8,020
Total expenses	47,248	35,145	93,377	74,706
Income before (benefit from) provision for income taxes	(35,498)	(12,017)	(69,246)	(40,466)
Acquisition of:
Segment assets at end of quarter	66,382	88,505	66,382	88,505
Capitalized software		138		251
Furniture, fixtures, equipment and building improvements	348	28	503	85
Amortization of capitalized software	103	457	197	949
Corporate and other | Furniture, Fixtures, Equipment and Building Improvements
Acquisition of:
Depreciation and amortization of furniture, fixtures, equipment and building improvements	$ 290	$ 332	$ 592	$ 659