Fair Value - Financial Statement Items Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets:
Short-term investment at fair value	$ 8,088	$ 12,194
Loans held for sale	4,270,494	3,509,300
Derivative assets:
Derivative asset, before netting	140,571	157,995
Netting	(55,054)	(58,992)
Total derivative assets	85,517	99,003
Investment in PennyMac Mortgage Investment Trust	1,011	929
Derivative liabilities:
Derivative liability, before netting	64,634	83,246
Netting	(42,595)	(61,534)
Net amounts of liabilities presented in the consolidated balance sheet	22,039	21,712
Mortgage servicing liabilities	1,940	2,096
Interest rate lock commitments
Derivative assets:
Total derivative assets	41,379	36,728
Forward contracts | Purchases
Derivative assets:
Derivative asset, before netting	2,545	2,433
Derivative liabilities:
Derivative liability, before netting	45,997	48,670
Forward contracts | Sales
Derivative assets:
Derivative asset, before netting	67,764	80,754
Derivative liabilities:
Derivative liability, before netting	7,894	20,684
MBS put options
Derivative assets:
Derivative asset, before netting	2,790	6,057
Call options on Eurodollar futures | Purchases
Derivative assets:
Derivative asset, before netting	844	2,820
Put options on Eurodollar futures | Purchases
Derivative assets:
Derivative asset, before netting	25,249	29,203
Put options on Eurodollar futures | Sales
Derivative liabilities:
Derivative liability, before netting		3,008
Level 3
Assets:
Loans held for sale	392,758	345,772
Recurring basis
Assets:
Short-term investment at fair value	8,088	12,194
Loans held for sale	4,270,494	3,509,300
Derivative assets:
Derivative asset, before netting	140,571	157,995
Netting	(55,054)	(58,992)
Total derivative assets	85,517	99,003
Mortgage servicing rights at fair value	6,510,585	5,953,621
Total assets	10,875,695	9,575,047
Derivative liabilities:
Derivative liability, before netting	64,634	83,246
Netting	(42,595)	(61,534)
Net amounts of liabilities presented in the consolidated balance sheet	22,039	21,712
Mortgage servicing liabilities	1,940	2,096
Total liabilities	23,979	23,808
Recurring basis | Related Party | PennyMac Mortgage Investment Trust
Derivative assets:
Investment in PennyMac Mortgage Investment Trust	1,011	929
Recurring basis | Interest rate lock commitments
Derivative assets:
Derivative asset, before netting	41,379	36,728
Derivative liabilities:
Derivative liability, before netting	10,743	10,884
Recurring basis | Forward contracts | Purchases
Derivative assets:
Derivative asset, before netting	2,545	2,433
Derivative liabilities:
Derivative liability, before netting	45,997	48,670
Recurring basis | Forward contracts | Sales
Derivative assets:
Derivative asset, before netting	67,764	80,754
Derivative liabilities:
Derivative liability, before netting	7,894	20,684
Recurring basis | MBS put options
Derivative assets:
Derivative asset, before netting	2,790	6,057
Recurring basis | Call options on Eurodollar futures | Purchases
Derivative assets:
Derivative asset, before netting	844	2,820
Recurring basis | Put options on Eurodollar futures | Purchases
Derivative assets:
Derivative asset, before netting	25,249	29,203
Recurring basis | Put options on Eurodollar futures | Sales
Derivative liabilities:
Derivative liability, before netting		3,008
Recurring basis | Level 1
Assets:
Short-term investment at fair value	8,088	12,194
Derivative assets:
Derivative asset, before netting	26,093	32,023
Total derivative assets	26,093	32,023
Total assets	35,192	45,146
Derivative liabilities:
Derivative liability, before netting		3,008
Net amounts of liabilities presented in the consolidated balance sheet		3,008
Total liabilities		3,008
Recurring basis | Level 1 | Related Party | PennyMac Mortgage Investment Trust
Derivative assets:
Investment in PennyMac Mortgage Investment Trust	1,011	929
Recurring basis | Level 1 | Call options on Eurodollar futures | Purchases
Derivative assets:
Derivative asset, before netting	844	2,820
Recurring basis | Level 1 | Put options on Eurodollar futures | Purchases
Derivative assets:
Derivative asset, before netting	25,249	29,203
Recurring basis | Level 1 | Put options on Eurodollar futures | Sales
Derivative liabilities:
Derivative liability, before netting		3,008
Recurring basis | Level 2
Assets:
Loans held for sale	3,877,736	3,163,528
Derivative assets:
Derivative asset, before netting	73,099	89,244
Total derivative assets	73,099	89,244
Total assets	3,950,835	3,252,772
Derivative liabilities:
Derivative liability, before netting	53,891	69,354
Net amounts of liabilities presented in the consolidated balance sheet	53,891	69,354
Total liabilities	53,891	69,354
Recurring basis | Level 2 | Forward contracts | Purchases
Derivative assets:
Derivative asset, before netting	2,545	2,433
Derivative liabilities:
Derivative liability, before netting	45,997	48,670
Recurring basis | Level 2 | Forward contracts | Sales
Derivative assets:
Derivative asset, before netting	67,764	80,754
Derivative liabilities:
Derivative liability, before netting	7,894	20,684
Recurring basis | Level 2 | MBS put options
Derivative assets:
Derivative asset, before netting	2,790	6,057
Recurring basis | Level 3
Assets:
Loans held for sale	392,758	345,772
Derivative assets:
Derivative asset, before netting	41,379	36,728
Total derivative assets	41,379	36,728
Mortgage servicing rights at fair value	6,510,585	5,953,621
Total assets	6,944,722	6,336,121
Derivative liabilities:
Derivative liability, before netting	10,743	10,884
Net amounts of liabilities presented in the consolidated balance sheet	10,743	10,884
Mortgage servicing liabilities	1,940	2,096
Total liabilities	12,683	12,980
Recurring basis | Level 3 | Interest rate lock commitments
Derivative assets:
Derivative asset, before netting	41,379	36,728
Derivative liabilities:
Derivative liability, before netting	$ 10,743	$ 10,884