Interest Income and Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Interest Income (Expense), Operating [Abstract]
Loans held for investment, net	$ 311,079	$ 313,034	$ 617,221	$ 608,086
Investment securities	117,858	116,204	236,393	224,531
Interest-bearing cash and federal funds sold	37,817	24,995	92,158	47,720
Margin balances	13,956	15,352	28,160	30,223
Financial instruments owned	6,345	4,631	11,205	8,352
Other	11,097	8,554	19,843	15,422
Total interest income	498,152	482,770	1,004,980	934,334
Bank deposits	220,287	171,362	450,351	308,650
Senior notes	12,507	12,506	25,013	25,012
Other	14,535	7,222	26,620	12,426
Total interest expense	$ 247,329	$ 191,090	$ 501,984	$ 346,088