Segments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) segment	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segments and Related Information
Number of segments | segment	3
Revenues:
Net gains on loans held for sale at fair value	$ 298,459	$ 754,341
Loan origination fees	67,858	104,037
Fulfillment fees from PennyMac Mortgage Investment Trust	16,754	60,835
Net loan servicing fees	286,309	39,720
Net interest income (expense):
Interest income	53,882	82,081
Interest expense, before non-segment activities	77,307	107,713
Net interest expense, before non-segment activities	(23,425)	(25,632)
Management fees from PennyMac Mortgage Investment Trust	8,117	8,449
Other	3,432	2,936
Total net revenues, before non-segment activities	657,504	944,686
Expenses	422,984	438,678
Income before provision for income taxes	234,520	506,008
Assets:
Segment assets at year end	14,617,902		$ 18,776,612
PennyMac Mortgage Investment Trust
Revenues:
Net gains on loans held for sale at fair value	$ (9,652)	(14,248)
Net interest income (expense):
Interest income		387
Mortgage banking
Segments and Related Information
Number of segments | segment	2
Operating segment
Assets:
Segment assets at year end	$ 14,617,902	31,297,980
Operating segment | Investment management
Net interest income (expense):
Interest expense, before non-segment activities		3
Net interest expense, before non-segment activities		(3)
Management fees from PennyMac Mortgage Investment Trust	8,117	8,449
Other	2,031	1,142
Total net revenues, before non-segment activities	10,148	9,588
Expenses	10,051	8,219
Income before provision for income taxes	97	1,369
Assets:
Segment assets at year end	22,646	18,271
Operating segment | Mortgage banking
Revenues:
Net gains on loans held for sale at fair value	298,459	754,341
Loan origination fees	67,858	104,037
Fulfillment fees from PennyMac Mortgage Investment Trust	16,754	60,835
Net loan servicing fees	286,309	39,720
Net interest income (expense):
Interest income	53,882	82,081
Interest expense, before non-segment activities	77,307	107,710
Net interest expense, before non-segment activities	(23,425)	(25,629)
Other	1,401	1,794
Total net revenues, before non-segment activities	647,356	935,098
Expenses	412,933	430,459
Income before provision for income taxes	234,423	504,639
Assets:
Segment assets at year end	14,595,256	31,279,709
Operating segment | Mortgage banking Production
Revenues:
Net gains on loans held for sale at fair value	221,610	515,963
Loan origination fees	67,858	104,037
Fulfillment fees from PennyMac Mortgage Investment Trust	16,754	60,835
Net interest income (expense):
Interest income	30,941	29,531
Interest expense, before non-segment activities	27,059	38,072
Net interest expense, before non-segment activities	3,882	(8,541)
Other	785	597
Total net revenues, before non-segment activities	310,889	672,891
Expenses	301,619	309,996
Income before provision for income taxes	9,270	362,895
Assets:
Segment assets at year end	4,905,974	8,886,460
Operating segment | Mortgage banking Servicing
Revenues:
Net gains on loans held for sale at fair value	76,849	238,378
Net loan servicing fees	286,309	39,720
Net interest income (expense):
Interest income	22,941	52,550
Interest expense, before non-segment activities	50,248	69,638
Net interest expense, before non-segment activities	(27,307)	(17,088)
Other	616	1,197
Total net revenues, before non-segment activities	336,467	262,207
Expenses	111,314	120,463
Income before provision for income taxes	225,153	141,744
Assets:
Segment assets at year end	$ 9,689,282	$ 22,393,249