Summary of Significant Accounting Policies - Schedule of Company Recognized Revenue and Expense Associated with CFEs in Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Accounting Policy [Line Items]
Interest income	$ 50,213	$ 47,579	$ 153,152	$ 128,942
Realized and unrealized losses, net of recoveries	(38,346)	(37,258)	(87,894)	(76,173)	$ (122,541)	$ 54,761
Noninterest income (loss), net	10,721	7,631	17,880	48,759	$ 75,126	$ 208,983
Consolidated VIEs
Accounting Policy [Line Items]
Interest income	29,018	27,303	81,100	77,801
Interest expense	(9,143)	(6,163)	(22,091)	(16,593)
Realized and unrealized losses, net of recoveries	(24,928)	(24,983)	(53,544)	(50,165)
Noninterest income (loss), net	$ 767	$ 104	$ (1,797)	$ (3,678)