Asset-Backed Securities Issued - Schedule of Asset-Backed Securities Issued (Details) $ in Thousands	Jun. 30, 2024 USD ($) series trust	Dec. 31, 2023 USD ($) series trust
Debt Instrument [Line Items]
Principal Amount	$ 3,434,945	$ 3,249,158
CAFL
Debt Instrument [Line Items]
Number of bridge securitization trusts \| trust	2	2
Asset-backed securities issued
Debt Instrument [Line Items]
ABS Issued, Net	$ 11,555,550	$ 9,811,880
Asset-backed securities issued \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	(1,060,684)	(943,370)
Asset-backed securities issued \| Deferred Debt Issuance Costs
Debt Instrument [Line Items]
Unamortized debt discount and deferred debt issuance costs	(3,093)	(5,929)
Asset-backed securities issued \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	12,466,549	10,588,659
Asset-backed securities issued \| Interest-only certificates at fair value
Debt Instrument [Line Items]
ABS Issued, Net	152,778	172,520
Asset-backed securities issued \| Sequoia
Debt Instrument [Line Items]
ABS Issued, Net	$ 6,686,531	$ 4,568,660
Number of series \| series	48	42
Asset-backed securities issued \| Sequoia \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (757,641)	$ (635,260)
Asset-backed securities issued \| Sequoia \| Deferred Debt Issuance Costs
Debt Instrument [Line Items]
Unamortized debt discount and deferred debt issuance costs	$ 0	$ 0
Asset-backed securities issued \| Sequoia \| Minimum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	2.67%	2.67%
Asset-backed securities issued \| Sequoia \| Maximum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	6.71%	6.66%
Asset-backed securities issued \| Sequoia \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	$ 7,393,323	$ 5,151,646
Asset-backed securities issued \| Sequoia \| Interest-only certificates at fair value
Debt Instrument [Line Items]
ABS Issued, Net	50,849	52,274
Asset-backed securities issued \| CAFL
Debt Instrument [Line Items]
ABS Issued, Net	$ 3,058,191	$ 3,362,978
Number of series \| series	20	21
Asset-backed securities issued \| CAFL \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (200,903)	$ (209,740)
Asset-backed securities issued \| CAFL \| Deferred Debt Issuance Costs
Debt Instrument [Line Items]
Unamortized debt discount and deferred debt issuance costs	$ 0	$ (1,935)
Asset-backed securities issued \| CAFL \| Minimum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	2.31%	2.34%
Asset-backed securities issued \| CAFL \| Maximum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	7.89%	7.89%
Asset-backed securities issued \| CAFL \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	$ 3,172,393	$ 3,472,825
Asset-backed securities issued \| CAFL \| Interest-only certificates at fair value
Debt Instrument [Line Items]
ABS Issued, Net	86,701	101,828
Asset-backed securities issued \| Freddie Mac SLST
Debt Instrument [Line Items]
ABS Issued, Net	$ 1,204,834	$ 1,265,777
Number of series \| series	3	3
Principal Amount	$ 166,000	$ 182,000
Asset-backed securities issued \| Freddie Mac SLST \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	(84,650)	(72,742)
Asset-backed securities issued \| Freddie Mac SLST \| Deferred Debt Issuance Costs
Debt Instrument [Line Items]
Unamortized debt discount and deferred debt issuance costs	$ (3,093)	$ (3,994)
Asset-backed securities issued \| Freddie Mac SLST \| Minimum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	3.50%	3.50%
Asset-backed securities issued \| Freddie Mac SLST \| Maximum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	7.50%	7.50%
Asset-backed securities issued \| Freddie Mac SLST \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	$ 1,280,405	$ 1,328,657
Asset-backed securities issued \| Freddie Mac SLST \| Interest-only certificates at fair value
Debt Instrument [Line Items]
ABS Issued, Net	12,172	13,856
Asset-backed securities issued \| Freddie Mac K-Series
Debt Instrument [Line Items]
ABS Issued, Net	$ 387,791	$ 391,977
Range of weighted average interest rates, by series (as a percent)	3.41%	3.55%
Number of series \| series	1	1
Asset-backed securities issued \| Freddie Mac K-Series \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (13,392)	$ (14,985)
Asset-backed securities issued \| Freddie Mac K-Series \| Deferred Debt Issuance Costs
Debt Instrument [Line Items]
Unamortized debt discount and deferred debt issuance costs	0	0
Asset-backed securities issued \| Freddie Mac K-Series \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	398,127	402,400
Asset-backed securities issued \| Freddie Mac K-Series \| Interest-only certificates at fair value
Debt Instrument [Line Items]
ABS Issued, Net	3,056	4,562
Asset-backed securities issued \| HEI
Debt Instrument [Line Items]
ABS Issued, Net	$ 218,203	$ 222,488
Number of series \| series	2	2
Asset-backed securities issued \| HEI \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (4,098)	$ (10,643)
Asset-backed securities issued \| HEI \| Deferred Debt Issuance Costs
Debt Instrument [Line Items]
Unamortized debt discount and deferred debt issuance costs	$ 0	$ 0
Asset-backed securities issued \| HEI \| Minimum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	3.94%	3.86%
Asset-backed securities issued \| HEI \| Maximum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	6.77%	6.70%
Asset-backed securities issued \| HEI \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	$ 222,301	$ 233,131
Asset-backed securities issued \| HEI \| Interest-only certificates at fair value
Debt Instrument [Line Items]
ABS Issued, Net	0	0
Asset-backed securities issued \| CoreVest
Debt Instrument [Line Items]
Principal Amount	$ 417,000	$ 485,000