Short-Term Debt - Assets Sold Under Agreement to Repurchase (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Carrying value:
Net amounts of liabilities presented in the consolidated balance sheet	$ 5,768,570,000
Total loans sold under agreements to repurchase	5,764,157,000		$ 3,001,283,000
Loans held for sale	6,772,423,000		3,509,300,000
Servicing advances, net	547,158,000		696,753,000
Mortgage servicing rights, at fair value	6,003,390,000		5,953,621,000
Other Assets	513,241,000		417,907,000
Note Payable
During the period:
Average balance of assets sold under agreements to repurchase	2,092,056,000	$ 1,300,000,000
Carrying value:
Amortization of debt issuance costs	932,000	459,000
Loan Repo Facility
During the period:
Average balance of assets sold under agreements to repurchase	$ 3,508,262,000	$ 3,722,179,000
Weighted-average interest rate (as a percent)	6.54%	2.19%
Total interest expense	$ 59,223,000	$ 23,770,000
Maximum daily amount outstanding	5,768,570,000	7,289,147,000
Carrying value:
Net amounts of liabilities presented in the consolidated balance sheet	5,768,570,000		3,004,690,000
Unamortized debt issuance costs	(4,413,000)		(3,407,000)
Total loans sold under agreements to repurchase	$ 5,764,157,000		$ 3,001,283,000
Weighted average interest rate (as a percent)	6.44%		6.00%
Available borrowing capacity committed	$ 383,569,000		$ 1,078,927,000
Available borrowing capacity uncommitted	3,522,861,000		5,391,383,000
Available borrowing capacity	3,906,430,000		6,470,310,000
Amortization of debt issuance costs	2,600,000	$ 3,700,000
Asset Pledged as Collateral without Right
Carrying value:
Loans held for sale	6,668,418,000		3,442,847,000
Servicing advances, net	315,323,000		381,379,000
Mortgage servicing rights, at fair value	5,954,749,000		5,897,613,000
Other Assets	$ 31,909,000		$ 12,277,000
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:
Mortgage servicing rights, at fair value	$ 5,954,749,000		$ 5,897,613,000
Asset Pledged as Collateral without Right | Note Payable | Servicing advances
Carrying value:
Servicing advances, net	315,323,000		381,379,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Mortgage servicing rights
Carrying value:
Mortgage servicing rights, at fair value	5,365,294,000		5,339,513,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Servicing advances
Carrying value:
Servicing advances, net	315,323,000		381,379,000
Asset Pledged as Collateral without Right | Mortgage loans held for sale | Loan Repo Facility | Loans held for sale
Carrying value:
Loans held for sale	6,124,986,000		3,139,870,000
Asset Pledged as Collateral without Right | Deposits.
Carrying value:
Other Assets	31,909,000		12,277,000
Asset Pledged as Collateral without Right | Deposits. | Note Payable | Deposits
Carrying value:
Other Assets	21,074,000		12,277,000
Asset Pledged as Collateral without Right | Deposits. | Loan Repo Facility | Deposits
Carrying value:
Other Assets	$ 31,909,000		$ 12,277,000