Investment Securities - Purchases, Sales and Redemptions, and Principal Collections for All Investment Securities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Debt Securities, Available-for-sale [Line Items]
Purchases/fundings	$ 22,733	$ 13,826
Sales and redemptions	625	1,350
Principal collections	4,831	52,967
Securitization VIEs
Debt Securities, Available-for-sale [Line Items]
Purchases/fundings	0	(4,639)
Sales and redemptions	(3,865)	0
Principal collections	(51,286)	(72,120)
HTM Securities
Debt Securities, Available-for-sale [Line Items]
Purchases/fundings	16,206	9,799
Sales and redemptions	0	0
Principal collections	2,526	50,850
Equity Security
Debt Securities, Available-for-sale [Line Items]
Purchases/fundings	0	0
Sales and redemptions	625	1,350
Principal collections	0	0
RMBS \| Available-for-sale
Debt Securities, Available-for-sale [Line Items]
Purchases/fundings	0	0
Sales and redemptions	0	0
Principal collections	1,939	2,073
RMBS \| Fair value option
Debt Securities, Available-for-sale [Line Items]
Purchases/fundings	0	0
Sales and redemptions	0	0
Principal collections	8,175	10,080
CMBS \| Fair value option
Debt Securities, Available-for-sale [Line Items]
Purchases/fundings	6,527	8,666
Sales and redemptions	3,865	0
Principal collections	$ 43,477	62,084
CMBS \| Fair value option \| Consolidated Partnership
Debt Securities, Available-for-sale [Line Items]
Purchases/fundings		$ 3,400