Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash Flows From Operating Activities:
Net income	$ 163,575	$ 157,539
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	15,665	15,076
Amortization of loans and advances to financial advisors and other employees	37,143	34,057
Amortization of premium on investment portfolio	2,142	2,356
Provision for credit losses and allowance for loans and advances to financial advisors and other employees	5,269	4,920
Amortization of intangible assets	5,842	4,437
Deferred income taxes	(2,655)	13,069
Stock-based compensation	56,797	43,083
Losses/(gains) on sale of investments	373	(1,353)
Other, net	(5,974)	(6,157)
Receivables:
Brokerage clients	(34,495)	(34,435)
Brokers, dealers, and clearing organizations	(243,727)	(39,648)
Securities purchased under agreements to resell	(101,207)	(201,053)
Financial instruments owned, including those pledged	(312,114)	(242,050)
Loans originated as held for sale	(545,666)	(380,033)
Proceeds from loans held for sale	444,364	317,468
Loans and advances to financial advisors and other employees	(87,795)	(40,053)
Other assets	(98,281)	218
Increase/(decrease) in operating liabilities, net of liabilities assumed:
Brokerage clients	15,781	136,855
Brokers, dealers, and clearing organizations	46,495	3,369
Drafts	(10,149)	(21,883)
Financial instruments sold, but not yet purchased	184,538	199,064
Other liabilities and accrued expenses	(145,642)	(349,919)
Net cash used in operating activities	(609,721)	(385,073)
Cash Flows From Investing Activities:
Principal paydowns, calls, maturities, and sales of available-for-sale securities	45,431	47,416
Calls and principal paydowns of held-to-maturity securities	183,460	5,548
Sale or maturity of investments	4,830	0
Increase in loans held for investment, net	352,537	(250,052)
Payments for:
Purchase of fixed assets	(9,636)	(15,411)
Purchase of available-for-sale securities	(7,000)	(7,551)
Purchase of held-to-maturity securities	(88,500)	0
Purchase of investments	(3,590)	(10,919)
Acquisitions, net of cash received	(752)	(58,765)
Net cash provided by/(used in) investing activities	476,780	(289,734)
Cash Flows From Financing Activities:
Payment of contingent consideration	(708)	(5,037)
Increase in securities sold under agreements to repurchase	9,015	217,715
Increase in bank deposits, net	219,832	1,208,216
Increase in securities loaned	88,685	32,868
Tax payments related to shares withheld for stock-based compensation plans	(98,638)	(74,238)
Repurchase of common stock	(60,710)	(94,521)
Cash dividends on preferred stock	(9,320)	(9,320)
Cash dividends paid to common stock and equity-award holders	(63,065)	(47,009)
Net cash provided by financing activities	85,091	1,228,674
Effect of exchange rate changes on cash	(1,644)	3,429
Increase/(decrease) in cash, cash equivalents, and cash segregated for regulatory purposes	(49,494)	557,296
Cash, cash equivalents, and cash segregated for regulatory purposes at beginning of period	3,523,849	2,229,002
Cash, cash equivalents, and cash segregated for regulatory purposes at end of period	3,474,355	2,786,298
Supplemental disclosure of cash flow information:
Cash paid for interest	257,723	158,201
Cash paid for income taxes, net of refunds	114,746	4,037
Noncash financing activities:
Unit grants, net of forfeitures	$ 124,212	$ 143,638