Mortgage Servicing Rights and Mortgage Servicing Liabilities - Activity in MSRs at Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Activity in MSRs carried at fair value
Exchange of mortgage servicing spread for interest-only stripped mortgage-backed securities			$ 121,520	$ 98,066
Change in fair value due to:
Total change in fair value	$ 628,258	$ (221,096)	758,158	70,608
Mortgage servicing rights
Activity in MSRs carried at fair value
Balance at beginning of period	7,923,078	6,510,585	7,099,348	5,953,621
MSRs resulting from loan sales	578,982	450,936	1,532,709	1,299,992
Transfer of mortgage servicing rights relating to delinquent loans to Agency		(73)		(305)
Exchange of mortgage servicing spread for interest-only stripped mortgage-backed securities	(121,520)	(98,066)	(121,520)	(98,066)
Additions	457,462	352,797	1,411,189	1,201,621
Change in fair value due to:
Changes in inputs used in valuation model	(402,376)	398,807	(132,984)	427,426
Other changes in fair value	(225,872)	(177,833)	(625,261)	(498,312)
Total change in fair value	(628,248)	220,974	(758,245)	(70,886)
Balance at end of period	7,752,292	7,084,356	7,752,292	7,084,356
Unpaid principal balance of underlying loans at end of period	$ 410,031,301	$ 351,269,905	$ 410,031,301	$ 351,269,905
Asset Pledged as Collateral without Right
Change in fair value due to:
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable		Notes Payable		Notes Payable
Asset Pledged as Collateral without Right | Mortgage servicing rights
Activity in MSRs carried at fair value
Balance at beginning of period			$ 7,033,892
Change in fair value due to:
Balance at end of period	$ 7,656,519		$ 7,656,519
Assets, Pledging Purpose [Extensible Enumeration]	Notes Payable		Notes Payable		Notes Payable