Mortgage Servicing Rights and Mortgage Servicing Liabilities - Activity in MSRs at Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Activity in MSRs carried at fair value
Exchange of mortgage servicing spread for interest-only stripped mortgage-backed securities				$ 121,520
Change in fair value due to:
Total change in fair value	$ 392,174	$ 628,258	$ 1,070,300	758,158
Mortgage servicing rights
Activity in MSRs carried at fair value
Balance at beginning of quarter	9,531,249	7,923,078	8,744,528	7,099,348
MSRs resulting from loan sales	700,326	578,982	2,165,213	1,532,709
Exchange of mortgage servicing spread for interest-only stripped mortgage-backed securities		(121,520)		(121,520)
Sale of MSRs Non-affiliates	183,514		183,514
Sale of MSRs to PennyMac Mortgage Investment Trust	1,895		1,895
Additions	514,917	457,462	1,979,804	1,411,189
Change in fair value due to:
Changes in inputs used in valuation model	(102,519)	(402,376)	(292,058)	(132,984)
Other changes in fair value	(289,705)	(225,872)	(778,332)	(625,261)
Total change in fair value	(392,224)	(628,248)	(1,070,390)	(758,245)
Balance at end of quarter	9,653,942	7,752,292	9,653,942	7,752,292
Unpaid principal balance of underlying loans at end of quarter	$ 470,281,735	$ 410,031,301	$ 470,281,735	$ 410,031,301
Asset Pledged as Collateral without Right
Change in fair value due to:
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable		Notes Payable		Notes Payable
Asset Pledged as Collateral without Right | Mortgage servicing rights
Activity in MSRs carried at fair value
Balance at beginning of quarter			$ 8,609,388
Change in fair value due to:
Balance at end of quarter	$ 9,440,264		$ 9,440,264
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable		Notes Payable		Notes Payable