Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash Flows From Operating Activities:
Net income	$ 662,155	$ 824,858	$ 503,472
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	50,615	45,574	40,863
Amortization of loans and advances to financial advisors and other employees	132,012	114,690	103,983
Amortization of premium on investment portfolio	12,156	17,042	20,739
Provision for credit losses and allowance for loans and advances to financial advisors and other employees	33,506	(11,502)	33,925
Amortization of intangible assets	19,595	18,188	19,620
Deferred income taxes	12,693	32,104	(39,071)
Stock-based compensation	135,505	119,384	108,217
Unrealized losses on investments	11,892	2,999	18,908
Other, net	8,852	26,222	(10,326)
Receivables:
Brokerage clients, net	228,492	(214,033)	415,286
Brokers, dealers, and clearing organizations	156,165	(8,496)	78,298
Securities purchased under agreements to resell	231,704	(266,801)	167,078
Financial instruments owned, including those pledged	425,252	(271,475)	278,904
Loans originated as held for sale	(576,153)	(1,997,561)	(3,019,290)
Proceeds from mortgages held for sale	593,086	2,313,934	2,894,742
Loans and advances to financial advisors and other employees	(132,384)	(172,553)	(179,995)
Other assets	(66,020)	(96,700)	(117,471)
Increase/(decrease) in operating liabilities, net of liabilities assumed:
Brokerage clients	(201,588)	(92,015)	323,493
Brokers, dealers, and clearing organizations	(81,661)	6,535	(71,144)
Drafts	(20,405)	4,880	(2,021)
Financial instruments sold, but not yet purchased	(301,333)	229,708	(224,874)
Other liabilities and accrued expenses	(176,721)	247,112	318,480
Net cash provided by operating activities	1,157,415	872,094	1,661,816
Cash Flows From Investing Activities:
Principal paydowns, calls, maturities, and sales of available-for-sale securities	330,049	562,352	896,746
Calls and principal paydowns of held-to-maturity securities	114,741	1,751,313	159,964
Sale of fixed assets	0	148,375	0
Sale or maturity of investments	20,753	19,606	2,139
Disposition of business	0	0	37,000
Increase in loans held for investment, net	(3,822,654)	(5,609,314)	(1,441,303)
Payments for:
Purchase of available-for-sale securities	(103,339)	(813,657)	(864,200)
Purchase of held-to-maturity securities	(754,306)	(2,668,221)	(384,700)
Purchase of investments	(15,551)	(23,309)	(21,317)
Purchase of fixed assets	(82,327)	(188,176)	(73,364)
Acquisitions, net of cash received	(11,903)	(144,471)	(280)
Net cash used in investing activities	(4,324,537)	(6,965,502)	(1,689,315)
Cash Flows from Financing Activities:
Increase/(decrease) in securities sold under agreements to repurchase	(173,517)	135,588	(200,679)
Increase in bank deposits, net	3,836,763	5,883,851	2,063,916
Increase/(decrease) in securities loaned	(81,114)	4,095	(463,210)
Tax payments related to shares withheld for stock-based compensation plans	(102,546)	(78,565)	(75,838)
Repurchase of common stock	(105,831)	(172,741)	(58,261)
Cash dividends on preferred stock	(37,281)	(35,587)	(27,261)
Cash dividends paid to common stock and equity-award holders	(133,747)	(66,336)	(46,497)
Payment of contingent consideration	(11,313)	(16,798)	(28,221)
Other financing, net	0	140,888	34,924
Net cash provided by financing activities	3,191,414	5,794,395	1,198,873
Effect of exchange rate changes on cash	55,053	(3,536)	6,862
Increase/(decrease) in cash, cash equivalents, and cash segregated for regulatory purposes	79,345	(302,549)	1,178,236
Cash, cash equivalents, and cash segregated for regulatory purposes at beginning of year	2,149,657	2,452,206	1,273,970
Cash, cash equivalents, and cash segregated for regulatory purposes at end of year	2,229,002	2,149,657	2,452,206
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds	217,133	288,950	160,007
Cash paid for interest	220,851	62,510	84,821
Noncash investing and financing activities:
Unit grants, net of forfeitures	194,741	156,535	125,033
Issuance of common stock for acquisitions	$ 0	$ 90,000	$ 0