Long-Term Debt - Note Payable (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 16, 2022
During the year:
Unpaid principal balance	$ 5,441,126,000
Carrying value:
Notes payable	1,972,020,000		$ 1,873,415,000
Unsecured senior notes	2,521,031,000		2,519,651,000
Servicing advances, net	499,955,000		694,038,000
Mortgage servicing rights, at fair value	$ 7,483,210,000		$ 7,099,348,000
Assets, Pledging Purpose [Extensible Enumeration]	Notes payable		Notes payable
Other Assets	$ 623,368,000		$ 582,460,000
Notes payable
Repayments of Notes Payable	625,000,000	$ 150,000,000
Asset Pledged as Collateral without Right
Carrying value:
Servicing advances, net	271,947,000		354,831,000
Mortgage servicing rights, at fair value	$ 7,406,892,000		$ 7,033,892,000
Assets, Pledging Purpose [Extensible Enumeration]	Notes payable		Notes payable
Other Assets	$ 16,175,000		$ 15,653,000
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 | Deposits.
Carrying value:
Other Assets	$ 16,175,000		$ 15,653,000
Note Payable
During the year:
Average balance	$ 1,950,330,000	$ 2,092,056,000
Weighted-average interest rate (as a percent)	8.92%	7.72%
Total interest expense	$ 44,006,000	$ 40,778,000
Carrying value:
Unpaid principal balance	1,980,000,000		1,880,000,000
Unamortized debt issuance costs	(7,980,000)		(6,585,000)
Notes payable	$ 1,972,020,000		$ 1,873,415,000
Weighted-average interest rate (as a percent)	8.69%		8.82%
Amortization of Financing Costs	$ 750,000	932,000
Notes payable
Maximum loan amount	1,730,000,000
Note Payable | SOFR
Notes payable
Maximum loan amount				$ 400,000,000
Committed amount of debt instrument				$ 350,000,000
Note Payable | Asset Pledged as Collateral without Right | Mortgage servicing rights
Carrying value:
Mortgage servicing rights, at fair value	7,406,892,000		$ 7,033,892,000
Note Payable | Asset Pledged as Collateral without Right | Servicing advances
Carrying value:
Servicing advances, net	271,947,000		354,831,000
Note Payable | Asset Pledged as Collateral without Right | Deposits. | Deposits
Carrying value:
Other Assets	16,175,000		15,653,000
Notes Payable Term Loan 2022-GT1 | SOFR
Long-Term debt
Maximum loan amount	$ 500,000,000
Notes payable
Interest rate spread	4.25%
Notes Payable Term Loan 2024-GT1 | SOFR
Notes payable
Maximum loan amount	$ 425,000,000
Interest rate spread	3.20%
Notes Payable Term Loan 2023-GT1 | SOFR
Notes payable
Maximum loan amount	$ 680,000,000
Interest rate spread	3.00%
Notes Payable Term Loan 2023-GT2 | SOFR
Notes payable
Maximum loan amount	$ 125,000,000
Interest rate spread	3.00%
Unsecured Senior Note
During the year:
Average balance	$ 2,550,000,000	$ 1,800,000,000
Weighted-average interest rate (as a percent)	5.90%	5.07%
Total interest expense	$ 38,832,000	$ 23,428,000
Unpaid principal balance	2,550,000,000		2,550,000,000
Unamortized debt issuance costs and premiums	(28,969,000)		(30,349,000)
Debt Instrument Unamortized Premium And Debt Issuance Costs Net	$ 2,521,031,000		$ 2,519,651,000
Weighted average interest rate (as a percent)	5.90%		5.90%
Carrying value:
Amortization of Financing Costs	$ 1,400,000	$ 913,000
Notes payable
Maximum loan amount	$ 2,550,000,000
Redemption rate (as a percent)	100.00%
Unsecured Senior Note | Before October 15, 2022 with up to 40% principal redeemed
Notes payable
Redemption rate (as a percent)	40.00%
Unsecured Senior Notes One Due October 2025
Notes payable
Maximum loan amount	$ 500,000,000
Interest rate spread	5.375%
Unsecured Senior Notes Two Due October 2025
Notes payable
Maximum loan amount	$ 150,000,000
Interest rate spread	5.375%
Unsecured Senior Notes Due February 2029
Notes payable
Maximum loan amount	$ 650,000,000
Interest rate spread	4.25%
Unsecured Senior Notes Due September 2031
Notes payable
Maximum loan amount	$ 500,000,000
Interest rate spread	5.75%
Unsecured Senior Notes Due December 2029
Notes payable
Maximum loan amount	$ 750,000,000
Interest rate spread	7.875%
Term Notes and Term Loans
Carrying value:
Unpaid principal balance	$ 1,730,000,000		$ 1,730,000,000
Freddie Mac MSR Note Payable
Carrying value:
Unpaid principal balance	$ 250,000,000		$ 150,000,000