Net Interest (Expense) Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Interest income:
Interest income	$ 248,753	$ 225,470	$ 660,553	$ 582,707
Interest expense:
Interest expense	249,900	217,597	697,559	591,237
Net interest (expense) income	(1,147)	7,873	(37,006)	(8,530)
Nonrelated Party
Interest income:
Cash and short-term investments	11,698	15,641	32,624	43,395
Principal-only stripped mortgage-backed securities	13,881	20,412	32,424	29,756
Loans held for sale	113,039	80,103	306,158	231,807
Placement fees relating to custodial funds	109,706	109,201	287,476	277,564
Other	429	113	1,871	185
Interest expense:
Assets sold under agreements to repurchase	121,170	102,708	328,084	279,730
Mortgage loan participation purchase and sale agreements	4,267	4,411	12,239	12,597
Notes payable secured by mortgage servicing assets	26,417	39,265	98,738	125,203
Unsecured senior notes	78,014	51,147	208,308	133,947
Interest shortfall on repayments of mortgage loans serviced for Agency securitizations	14,855	15,711	38,687	29,734
Interest on mortgage loan impound deposits	4,370	3,450	9,214	8,399
Other	807	905	2,289	1,627
Interest expense	249,900	217,597	697,559	591,237
Loan Repo Facility
Interest expense:
Assets sold under agreements to repurchase	$ 121,170	$ 102,708	$ 328,084	$ 279,730