Loans Held for Investment - Summary of Loan Balances (Details) $ in Thousands	Dec. 31, 2024 USD ($) loan	Dec. 31, 2023 USD ($) loan
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	103,571	112,572
Total Principal	$ 11,219,931	$ 11,876,358
Loans 30 To 89 Days Delinquent	997,052	1,034,307
Loans 90 or more days delinquent	$ 728,174	806,581
Seasoned Subprime Residential Mortgage Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Underlying mortgages excluded from portfolio		$ 152,000
Adjustable Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	5,668	6,215
Total Principal	$ 711,900	$ 777,417
Loans 30 To 89 Days Delinquent	52,121	55,098
Loans 90 or more days delinquent	$ 43,112	$ 41,571
Fixed Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	97,903	106,357
Total Principal	$ 10,508,031	$ 11,098,941
Loans 30 To 89 Days Delinquent	944,931	979,209
Loans 90 or more days delinquent	$ 685,062	$ 765,010
$1 To $250 | Adjustable Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	5,014	5,516
Total Principal	$ 378,205	$ 419,527
Loans 30 To 89 Days Delinquent	32,937	35,474
Loans 90 or more days delinquent	$ 21,166	$ 23,685
$1 To $250 | Adjustable Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	0.00%	0.00%
$1 To $250 | Adjustable Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	22.49%	22.99%
$1 To $250 | Fixed Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	89,619	97,952
Total Principal	$ 6,732,889	$ 7,365,418
Loans 30 To 89 Days Delinquent	634,115	694,682
Loans 90 or more days delinquent	$ 417,529	$ 477,229
$1 To $250 | Fixed Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	0.00%	0.00%
$1 To $250 | Fixed Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	20.80%	20.90%
$250 To $500 | Adjustable Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	453	487
Total Principal	$ 155,312	$ 169,269
Loans 30 To 89 Days Delinquent	11,578	9,648
Loans 90 or more days delinquent	$ 9,224	$ 7,137
$250 To $500 | Adjustable Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	2.38%	2.38%
$250 To $500 | Adjustable Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	15.25%	14.50%
$250 To $500 | Fixed Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	6,400	6,612
Total Principal	$ 2,135,750	$ 2,203,285
Loans 30 To 89 Days Delinquent	217,893	216,451
Loans 90 or more days delinquent	$ 154,989	$ 174,653
$250 To $500 | Fixed Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	0.00%	0.00%
$250 To $500 | Fixed Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	13.00%	13.00%
$500 To $750 | Adjustable Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	115	121
Total Principal	$ 68,427	$ 72,531
Loans 30 To 89 Days Delinquent	2,237	2,973
Loans 90 or more days delinquent	$ 5,272	$ 5,357
$500 To $750 | Adjustable Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	3.13%	3.00%
$500 To $750 | Adjustable Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	11.75%	10.00%
$500 To $750 | Fixed Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	1,000	1,000
Total Principal	$ 598,390	$ 598,053
Loans 30 To 89 Days Delinquent	36,395	30,687
Loans 90 or more days delinquent	$ 53,842	$ 55,958
$500 To $750 | Fixed Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	1.99%	1.99%
$500 To $750 | Fixed Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	12.99%	12.00%
$750 To $1,000 | Adjustable Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	37	37
Total Principal	$ 32,087	$ 31,910
Loans 30 To 89 Days Delinquent	2,703	2,685
Loans 90 or more days delinquent	$ 0	$ 0
$750 To $1,000 | Adjustable Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	2.88%	2.88%
$750 To $1,000 | Adjustable Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	12.38%	10.50%
$750 To $1,000 | Fixed Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	423	386
Total Principal	$ 366,673	$ 333,086
Loans 30 To 89 Days Delinquent	22,139	18,285
Loans 90 or more days delinquent	$ 15,374	$ 21,000
$750 To $1,000 | Fixed Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	2.00%	2.00%
$750 To $1,000 | Fixed Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	11.10%	11.99%
Over $1,000 | Adjustable Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	49	54
Total Principal	$ 77,869	$ 84,180
Loans 30 To 89 Days Delinquent	2,666	4,318
Loans 90 or more days delinquent	$ 7,450	$ 5,392
Over $1,000 | Adjustable Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	2.38%	2.38%
Over $1,000 | Adjustable Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	10.75%	9.25%
Over $1,000 | Fixed Rate Loans
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Number of loans | loan	461	407
Total Principal	$ 674,329	$ 599,099
Loans 30 To 89 Days Delinquent	34,388	19,104
Loans 90 or more days delinquent	$ 43,327	$ 36,170
Over $1,000 | Fixed Rate Loans | Minimum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	1.73%	1.73%
Over $1,000 | Fixed Rate Loans | Maximum
Securitized Loans Held For Investment By Consolidated Variable Interest Entities [Line Items]
Interest rate	11.25%	11.99%