Fair Value Measurement - Level Three Assets and Liabilities Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Beneficial interest liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	$ 8,485	$ 0	$ 4,221	$ 0
Additions	0	0	0	0
Repayments and settlements	(1,658)		(2,367)
Changes in fair value recorded in earnings	4,371	(85)	9,344	(85)
Fair value, ending balance	11,198	(85)	11,198	(85)
Beneficial Interests
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	62,214	0	41,012	0
Acquisition of beneficial interests	41,124	30,535	71,400	30,535
Repayments and settlements / Payments on beneficial interests	(1,729)		(1,729)
Charge-offs and changes in fair value recorded in earnings	(3,805)	(1,871)	(12,879)	(1,871)
Fair value, ending balance	97,804	28,664	97,804	28,664
Fair Value, Inputs, Level 3 | Payable to Securitization Note Holders
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	129,092	0	141,416	0
Repayments and settlements	(14,882)	0	(28,446)	0
Changes in fair value recorded in earnings	(558)	0	682	0
Fair value, ending balance	113,652	0	113,652	0
Fair Value, Inputs, Level 3 | Trailing Fee Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	4,244	4,449	4,251	4,852
Issuances	573	516	1,189	834
Repayments and settlements	(648)	(679)	(1,311)	(1,426)
Changes in fair value recorded in earnings	73	(21)	113	5
Fair value, ending balance	4,242	4,265	4,242	4,265
Fair Value, Inputs, Level 3 | Line of Credit Receivable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	0		0
Issuances	8,261		8,261
Charge-offs and changes in fair value recorded in earnings	44		44
Fair value, ending balance	8,305		8,305
Fair Value, Inputs, Level 3 | Notes receivable and residual certificates (at fair value)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	13,376	5,009	14,847	6,181
Repayments and settlements / Payments on beneficial interests	(1,456)	(1,430)	(2,681)	(2,996)
Charge-offs and changes in fair value recorded in earnings	(278)	328	(524)	722
Fair value, ending balance	$ 11,642	$ 3,907	$ 11,642	$ 3,907