Short-Term Debt - Assets Sold Under Agreement to Repurchase (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Carrying value:
Net amounts of liabilities presented in the consolidated balance sheet	$ 3,786,306,000		$ 3,786,306,000
Total loans sold under agreements to repurchase	3,780,524,000		3,780,524,000		$ 3,001,283,000
Loans held for sale	4,270,494,000		4,270,494,000		3,509,300,000
Servicing advances, net	500,122,000		500,122,000		696,753,000
Mortgage servicing rights, at fair value	6,510,585,000		6,510,585,000		5,953,621,000
Other Assets	593,698,000		593,698,000		417,907,000
Note Payable
During the period:
Average balance of assets sold under agreements to repurchase	2,480,000,000	$ 1,426,373,000	2,287,099,000	$ 1,363,536,000
Carrying value:
Amortization of debt issuance costs	809,000	548,000	1,700,000	1,000,000.0
Loan Repo Facility
During the period:
Average balance of assets sold under agreements to repurchase	$ 4,688,102,000	$ 2,215,595,000	$ 4,101,440,000	$ 2,964,727,000
Weighted-average interest rate (as a percent)	7.25%	2.80%	6.95%	2.42%
Total interest expense	$ 87,480,000	$ 18,949,000	$ 146,703,000	$ 42,719,000
Maximum daily amount outstanding	6,358,007,000	3,316,376,000	6,358,007,000	7,289,147,000
Carrying value:
Net amounts of liabilities presented in the consolidated balance sheet	3,786,306,000		3,786,306,000		3,004,690,000
Unamortized debt issuance costs	(5,782,000)		(5,782,000)		(3,407,000)
Total loans sold under agreements to repurchase	$ 3,780,524,000		$ 3,780,524,000		$ 3,001,283,000
Weighted average interest rate (as a percent)	6.87%		6.87%		6.00%
Available borrowing capacity committed	$ 1,284,131,000		$ 1,284,131,000		$ 1,078,927,000
Available borrowing capacity uncommitted	5,204,563,000		5,204,563,000		5,391,383,000
Available borrowing capacity	6,488,694,000		6,488,694,000		6,470,310,000
Amortization of debt issuance costs	2,800,000	$ 3,500,000	5,400,000	$ 7,100,000
Asset Pledged as Collateral without Right
Carrying value:
Loans held for sale	4,194,839,000		4,194,839,000		3,442,847,000
Servicing advances, net	288,082,000		288,082,000		381,379,000
Mortgage servicing rights, at fair value	6,457,553,000		6,457,553,000		5,897,613,000
Other Assets	$ 38,118,000		$ 38,118,000		$ 12,277,000
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:
Mortgage servicing rights, at fair value	$ 6,457,553,000		$ 6,457,553,000		$ 5,897,613,000
Asset Pledged as Collateral without Right | Note Payable | Servicing advances
Carrying value:
Servicing advances, net	288,082,000		288,082,000		381,379,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Mortgage servicing rights
Carrying value:
Mortgage servicing rights, at fair value	5,774,905,000		5,774,905,000		5,339,513,000
Asset Pledged as Collateral without Right | Loan Repo Facility | Servicing advances
Carrying value:
Servicing advances, net	288,082,000		288,082,000		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	3,661,755,000		3,661,755,000		3,139,870,000
Asset Pledged as Collateral without Right | Deposits.
Carrying value:
Other Assets	38,118,000		38,118,000		12,277,000
Asset Pledged as Collateral without Right | Deposits. | Note Payable | Deposits
Carrying value:
Other Assets	31,561,000		31,561,000		12,277,000
Asset Pledged as Collateral without Right | Deposits. | Loan Repo Facility | Deposits
Carrying value:
Other Assets	$ 38,118,000		$ 38,118,000		$ 12,277,000