Net Interest Expense (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Interest income:
Interest income	$ 156,426,000	$ 128,478,000
Interest expense:
Interest expense	165,769,000	131,771,000
Net interest expense	(9,343,000)	(3,293,000)
Nonrelated Party
Interest income:
Cash and short-term investments	14,582,000	16,245,000
Principal-only stripped mortgage-backed securities	270,000
Loans held for sale at fair value	65,421,000	60,993,000
Placement fees relating to custodial funds	76,133,000	51,219,000
Interest expense:
Assets sold under agreements to repurchase	70,435,000	59,223,000
Mortgage loan participation purchase and sale agreements	4,077,000	2,923,000
Notes payable	44,006,000	40,778,000
Unsecured senior notes	38,832,000	23,428,000
Interest shortfall on repayments of mortgage loans serviced for Agency securitizations	6,121,000	3,210,000
Interest on mortgage loan impound deposits	1,987,000	1,967,000
Other	311,000	242,000
Interest expense	165,769,000	131,771,000
Related Party | Townsgate Closing Services, LLC
Interest income:
Interest income	20,000	21,000
Loan Repo Facility
Interest expense:
Assets sold under agreements to repurchase	$ 70,435,000	$ 59,223,000