Short-Term Debt - Assets Sold Under Agreement to Repurchase (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Carrying value:
Unpaid principal balance	$ 7,351,846,000		$ 7,351,846,000
Total loans sold under agreements to repurchase	7,344,254,000		7,344,254,000		$ 8,685,207,000
Loans held for sale	6,961,224,000		6,961,224,000		8,217,468,000
Servicing advances, net	430,602,000		430,602,000		568,512,000
Mortgage servicing rights, at fair value	9,531,249,000		9,531,249,000		8,744,528,000
Other Assets	714,677,000		$ 714,677,000		770,081,000
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	1,698,132,000	$ 1,872,857,000	$ 1,780,415,000	$ 1,911,593,000
Carrying value:
Amortization of debt issuance costs	2,700,000	726,000	3,200,000	1,500,000
Loan Repo Facility
During the period:
Average balance of assets sold under agreements to repurchase	$ 7,183,987,000	$ 5,761,107,000	$ 6,649,802,000	$ 4,651,823,000
Weighted-average interest rate	6.00%	7.06%	5.97%	7.13%
Total interest expense	$ 112,685,000	$ 106,587,000	$ 206,914,000	$ 177,022,000
Maximum daily amount outstanding	8,581,781,000	7,122,796,000	8,690,936,000	7,122,796,000
Carrying value:
Unpaid principal balance	7,351,846,000		7,351,846,000		8,692,756,000
Unamortized debt issuance costs	(7,592,000)		(7,592,000)		(7,549,000)
Total loans sold under agreements to repurchase	$ 7,344,254,000		$ 7,344,254,000		$ 8,685,207,000
Weighted average interest rate	5.94%		5.94%		5.89%
Available borrowing capacity committed	$ 1,017,655,000		$ 1,017,655,000		$ 460,000,000
Available borrowing capacity uncommitted	3,918,218,000		3,918,218,000		3,104,026,000
Available borrowing capacity	4,935,873,000		4,935,873,000		3,564,026,000
Amortization of debt issuance costs	5,100,000	$ 5,400,000	9,900,000	$ 12,100,000
Asset Pledged as Collateral without Right
Carrying value:
Loans held for sale	6,873,346,000		6,873,346,000		8,140,834,000
Servicing advances, net	$ 265,118,000		$ 265,118,000		$ 357,939,000
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable		Notes Payable		Notes Payable
Mortgage servicing rights, at fair value	$ 9,350,647,000		$ 9,350,647,000		$ 8,609,388,000
Other Assets	$ 13,124,000		$ 13,124,000		$ 16,697,000
Asset Pledged as Collateral without Right | Mortgage servicing rights
Carrying value:
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable		Notes Payable		Notes Payable
Asset Pledged as Collateral without Right | Note Payable | Mortgage servicing rights
Carrying value:
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable		Notes Payable		Notes Payable
Mortgage servicing rights, at fair value	$ 9,350,647,000		$ 9,350,647,000		$ 8,609,388,000
Asset Pledged as Collateral without Right | Note Payable | Servicing advances
Carrying value:
Servicing advances, net	265,118,000		265,118,000		357,939,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Principal-only stripped MBS
Carrying value:
Principal-only stripped MBS	784,958,000		784,958,000		825,865,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Mortgage servicing rights
Carrying value:
Mortgage servicing rights, at fair value	8,034,225,000		8,034,225,000		7,488,539,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Servicing advances
Carrying value:
Servicing advances, net	265,118,000		265,118,000		357,939,000
Asset Pledged as Collateral without Right | Mortgage loans held for sale | Loan Repo Facility | Loans held for sale
Carrying value:
Loans held for sale	6,128,283,000		6,128,283,000		7,612,832,000
Asset Pledged as Collateral without Right | Deposits.
Carrying value:
Other Assets	13,124,000		13,124,000		16,697,000
Asset Pledged as Collateral without Right | Deposits. | Deposits
Carrying value:
Other Assets	13,124,000		13,124,000		16,697,000
Asset Pledged as Collateral without Right | Deposits. | Loan Repo Facility | Deposits
Carrying value:
Other Assets	$ 13,124,000		$ 13,124,000		$ 16,697,000