Short-Term Debt - Assets Sold Under Agreement to Repurchase (Details) - USD ($)	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Carrying value:
Unpaid principal balance	$ 7,064,948,000
Total loans sold under agreements to repurchase	7,058,053,000		$ 8,685,207,000
Loans held for sale	7,095,270,000		8,217,468,000
Servicing advances, net	496,917,000		568,512,000
Mortgage servicing rights, at fair value	8,963,889,000		8,744,528,000
Other Assets	$ 663,363,000		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	$ 1,863,611,000	$ 1,950,330,000
Carrying value:
Amortization of debt issuance costs	513,000	750,000
Loan Repo Facility
During the period:
Average balance of assets sold under agreements to repurchase	$ 6,109,683,000	$ 3,542,537,000
Weighted-average interest rate	5.94%	7.24%
Total interest expense	$ 94,229,000	$ 70,435,000
Maximum daily amount outstanding	8,589,915,000	5,442,438,000
Carrying value:
Unpaid principal balance	7,064,948,000		8,692,756,000
Unamortized debt issuance costs	(6,895,000)		(7,549,000)
Total loans sold under agreements to repurchase	$ 7,058,053,000		$ 8,685,207,000
Weighted average interest rate	5.80%		5.89%
Available borrowing capacity committed	$ 1,117,467,000		$ 460,000,000
Available borrowing capacity uncommitted	4,613,856,000		3,104,026,000
Available borrowing capacity	5,731,323,000		3,564,026,000
Amortization of debt issuance costs	4,800,000	$ 6,700,000
Asset Pledged as Collateral without Right
Carrying value:
Loans held for sale	7,027,759,000		8,140,834,000
Servicing advances, net	$ 303,106,000		$ 357,939,000
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable		Notes Payable
Mortgage servicing rights, at fair value	$ 8,802,948,000		$ 8,609,388,000
Other Assets	$ 13,768,000		$ 16,697,000
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:
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable		Notes Payable
Mortgage servicing rights, at fair value	$ 8,802,948,000		$ 8,609,388,000
Asset Pledged as Collateral without Right | Note Payable | Servicing advances
Carrying value:
Servicing advances, net	303,106,000		357,939,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Principal-only stripped MBS
Carrying value:
Principal-only stripped MBS	817,596,000		825,865,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Mortgage servicing rights
Carrying value:
Mortgage servicing rights, at fair value	7,636,201,000		7,488,539,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Servicing advances
Carrying value:
Servicing advances, net	303,106,000		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	6,485,146,000		7,612,832,000
Asset Pledged as Collateral without Right | Deposits.
Carrying value:
Other Assets	13,768,000		16,697,000
Asset Pledged as Collateral without Right | Deposits. | Deposits
Carrying value:
Other Assets	13,768,000		16,697,000
Asset Pledged as Collateral without Right | Deposits. | Loan Repo Facility | Deposits
Carrying value:
Other Assets	$ 13,768,000		$ 16,697,000