Short-Term Debt - Assets Sold Under Agreement to Repurchase (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Carrying value:
Unpaid principal balance	$ 8,692,756
Total loans sold under agreements to repurchase	8,685,207	$ 3,763,956
Loans held for sale	8,217,468	4,420,691
Servicing advances, net	568,512	694,038
Mortgage servicing rights, at fair value	8,744,528	7,099,348
Other Assets	$ 770,081	582,460
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]	us-gaap:SecuredOvernightFinancingRateSofrMember
Note Payable
During the period:
Average balance of assets sold under agreements to repurchase	$ 1,848,374	2,421,124	$ 1,584,383
Carrying value:
Amortization of debt issuance costs	2,900	3,200	2,500
Loan Repo Facility
During the period:
Average balance of assets sold under agreements to repurchase	$ 5,474,998	$ 3,701,448	$ 2,580,513
Weighted-average interest rate	6.79%	7.12%	3.59%
Total interest expense	$ 393,977	$ 279,289	$ 105,459
Maximum daily amount outstanding	8,591,735	6,358,007	7,289,147
Carrying value:
Unpaid principal balance	8,692,756	3,769,449
Unamortized debt issuance costs and premiums	(7,549)	(5,493)
Total loans sold under agreements to repurchase	$ 8,685,207	$ 3,763,956
Weighted average interest rate	5.89%	7.05%
Available borrowing capacity committed	$ 460,000	$ 1,282,040
Available borrowing capacity uncommitted	3,104,026	5,548,511
Available borrowing capacity	3,564,026	6,830,551
Amortization of debt issuance costs	22,200	15,700	$ 12,900
Asset Pledged as Collateral without Right
Carrying value:
Loans held for sale	8,140,834	4,329,501
Servicing advances, net	$ 357,939	$ 354,831
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable	Notes Payable
Mortgage servicing rights, at fair value	$ 8,609,388	$ 7,033,892
Other Assets	$ 16,697	$ 15,653
Asset Pledged as Collateral without Right | Mortgage servicing rights
Carrying value:
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable	Notes Payable
Asset Pledged as Collateral without Right | Mortgage servicing rights
Carrying value:
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable	Notes Payable
Asset Pledged as Collateral without Right | Note Payable | Mortgage servicing rights
Carrying value:
Mortgage servicing rights, at fair value	$ 8,609,388	$ 7,033,892
Asset Pledged as Collateral without Right | Note Payable | Servicing advances
Carrying value:
Servicing advances, net	357,939	354,831
Asset Pledged as Collateral without Right | Loan Repo Facility | Servicing advances
Carrying value:
Servicing advances, net	357,939	354,831
Asset Pledged as Collateral without Right | Loan Repo Facility | Mortgage servicing rights
Carrying value:
Mortgage servicing rights, at fair value	7,488,539	6,284,239
Asset Pledged as Collateral without Right | Mortgage loans held for sale | Loan Repo Facility | Principal-only stripped MBS
Carrying value:
Loans held for sale	825,865
Asset Pledged as Collateral without Right | Mortgage loans held for sale | Loan Repo Facility | Loans held for sale
Carrying value:
Loans held for sale	7,612,832	3,858,977
Asset Pledged as Collateral without Right | Deposits.
Carrying value:
Other Assets	16,697	15,653
Asset Pledged as Collateral without Right | Deposits. | Loan Repo Facility | Deposits
Carrying value:
Other Assets	$ 16,697	$ 15,653