Asset-Backed Securities Issued - Components of Asset-Backed Securities Issued by Consolidated Securitization Entities Sponsored, Along With Other Selected Information (Details) - Asset-backed securities issued $ in Thousands	Sep. 30, 2023 USD ($) series	Dec. 31, 2022 USD ($) series
Debt Instrument [Line Items]
ABS Issued, Net	$ 8,392,050	$ 7,986,752
Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	(1,328,889)	(1,163,285)
Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	9,544,732	8,944,351
Interest-only certificates
Debt Instrument [Line Items]
ABS Issued, Net	176,207	205,686
Legacy Sequoia
Debt Instrument [Line Items]
ABS Issued, Net	$ 149,202	$ 184,191
Number of series \| series	20	20
Legacy Sequoia \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (10,915)	$ (16,036)
Legacy Sequoia \| Minimum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	3.73%	2.69%
Legacy Sequoia \| Maximum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	7.26%	5.19%
Legacy Sequoia \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	$ 159,990	$ 200,047
Legacy Sequoia \| Interest-only certificates
Debt Instrument [Line Items]
ABS Issued, Net	127	180
Sequoia
Debt Instrument [Line Items]
ABS Issued, Net	$ 3,568,505	$ 2,971,109
Number of series \| series	20	17
Sequoia \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (866,568)	$ (682,477)
Sequoia \| Minimum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	2.67%	2.57%
Sequoia \| Maximum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	6.01%	6.13%
Sequoia \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	$ 4,384,081	$ 3,595,715
Sequoia \| Interest-only certificates
Debt Instrument [Line Items]
ABS Issued, Net	50,992	57,871
CAFL
Debt Instrument [Line Items]
ABS Issued, Net	$ 3,134,929	$ 3,115,807
Number of series \| series	20	19
CAFL \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (301,241)	$ (331,371)
CAFL \| Minimum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	2.34%	2.34%
CAFL \| Maximum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)	6.18%	5.92%
CAFL \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	$ 3,330,287	$ 3,322,250
CAFL \| Interest-only certificates
Debt Instrument [Line Items]
ABS Issued, Net	105,883	124,928
Freddie Mac SLST
Debt Instrument [Line Items]
ABS Issued, Net	$ 1,058,991	$ 1,222,150
Range of weighted average interest rates, by series (as a percent)	3.50%
Number of series \| series	2	3
Debt instrument, face amount		$ 86,000
Freddie Mac SLST \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (120,007)	$ (99,830)
Freddie Mac SLST \| Minimum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)		3.50%
Freddie Mac SLST \| Maximum
Debt Instrument [Line Items]
Range of weighted average interest rates, by series (as a percent)		4.75%
Freddie Mac SLST \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	1,165,093	$ 1,306,652
Freddie Mac SLST \| Interest-only certificates
Debt Instrument [Line Items]
ABS Issued, Net	13,905	15,328
Freddie Mac K-Series
Debt Instrument [Line Items]
ABS Issued, Net	$ 387,650	$ 392,785
Range of weighted average interest rates, by series (as a percent)	3.41%	3.41%
Number of series \| series	1	1
Freddie Mac K-Series \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (22,178)	$ (25,319)
Freddie Mac K-Series \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	404,528	410,725
Freddie Mac K-Series \| Interest-only certificates
Debt Instrument [Line Items]
ABS Issued, Net	5,300	7,379
HEI
Debt Instrument [Line Items]
ABS Issued, Net	$ 92,773	$ 100,710
Range of weighted average interest rates, by series (as a percent)	3.83%	3.78%
Number of series \| series	1	1
HEI \| Revision of Prior Period, Accounting Standards Update, Adjustment
Debt Instrument [Line Items]
ABS Issued, Net	$ (7,980)	$ (8,252)
HEI \| Certificates with principal balance
Debt Instrument [Line Items]
ABS Issued, Net	100,753	108,962
HEI \| Interest-only certificates
Debt Instrument [Line Items]
ABS Issued, Net	0	0
CoreVest
Debt Instrument [Line Items]
Debt instrument, face amount	$ 485,000	$ 485,000

Asset-Backed Securities Issued - Components of Asset-Backed Securities Issued by Consolidated Securitization Entities Sponsored, Along With Other Selected Information (Details) - Asset-backed securities issued
$ in Thousands