Net Interest Expense (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Interest income:
Interest income	$ 200,811,000	$ 172,952,000	$ 357,237,000	$ 301,430,000
Interest expense:
Interest expense	207,871,000	178,642,000	373,640,000	310,413,000
Net interest expense	(7,060,000)	(5,690,000)	(16,403,000)	(8,983,000)
Nonrelated Party
Interest income:
Cash and short-term investments	13,172,000	21,127,000	27,754,000	37,372,000
Principal-only stripped mortgage-backed securities	9,074,000		9,344,000
Loans held for sale at fair value	86,283,000	78,780,000	151,704,000	139,773,000
Placement fees relating to custodial funds	92,230,000	73,024,000	168,363,000	124,243,000
Other	52,000		52,000
Interest expense:
Assets sold under agreements to repurchase	106,587,000	87,480,000	177,022,000	146,703,000
Mortgage loan participation purchase and sale agreements	4,109,000	4,462,000	8,186,000	7,385,000
Notes payable	41,932,000	53,817,000	85,938,000	94,595,000
Unsecured senior notes	43,968,000	23,688,000	82,800,000	47,116,000
Interest shortfall on repayments of mortgage loans serviced for Agency securitizations	7,902,000	6,714,000	14,023,000	9,924,000
Interest on mortgage loan impound deposits	2,962,000	2,225,000	4,949,000	4,192,000
Other	411,000	256,000	722,000	498,000
Interest expense	207,871,000	178,642,000	373,640,000	310,413,000
Related Party | Townsgate Closing Services, LLC
Interest income:
Interest income	0	21,000	20,000	42,000
Loan Repo Facility
Interest expense:
Assets sold under agreements to repurchase	$ 106,587,000	$ 87,480,000	$ 177,022,000	$ 146,703,000