Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows From Operating Activities:
Net income	$ 315,003	$ 319,318
Receivables:
Brokerage clients	297,127	(194,655)
Brokers, dealers, and clearing organizations	183,105	(156,658)
Securities purchased under agreements to resell	(51,852)	75,851
Financial instruments owned, including those pledged	153,217	110,240
Loans originated as held for sale	(2,013,038)	(1,293,650)
Proceeds from mortgages held for sale	2,141,691	1,255,823
Loans and advances to financial advisors and other employees	(138,020)	(147,144)
Other assets	64,572	(41,002)
Increase/(decrease) in operating liabilities, net of liabilities assumed:
Brokerage clients	287,384	69,761
Brokers, dealers, and clearing organizations	(33,956)	56,711
Drafts	(29,060)	(20,072)
Financial instruments sold, but not yet purchased	(62,918)	(41,565)
Other liabilities and accrued expenses	(37,105)	(132,768)
Net cash provided by operating activities	1,334,524	33,305
Net cash provided by/(used in) operating activities	1,334,524	33,305
Depreciation and amortization	29,659	28,930
Amortization of loans and advances to financial advisors and other employees	76,728	69,286
Amortization of premium on investment portfolio	15,516	26,687
Provision for credit losses and allowance for loans and advances to financial advisors and other employees	35,066	5,837
Amortization of intangible assets	14,489	10,960
Deferred income taxes	(8,973)	(13,573)
Stock-based compensation	80,987	78,329
(Gains)/losses on sale of investments	22,828	(1,279)
Other, net	(7,926)	(32,062)
Cash Flows From Investing Activities:
Principal paydowns, sales, calls, and maturities of available-for-sale securities	781,922	1,034,741
Calls and principal paydowns of held-to-maturity securities	155,784	456,804
Sale of other real estate owned		7,300
Sale or maturity of investments	2,252	4,263
Disposition of business	37,000
Increase in loans held for investment, net	(1,075,568)	(592,547)
Payments for:
Purchase of fixed assets	(70,532)	(116,307)
Purchase of available-for-sale securities	(628,660)	(239,155)
Purchase of held-to-maturity securities	(384,700)	(243,335)
Purchase of investments	(21,317)	(9,100)
Acquisitions, net of cash received	(280)	(136,196)
Net cash (used in)/provided by investing activities	(1,204,099)	166,468
Cash Flows From Financing Activities:
Repayments of borrowings, net		(62,810)
Repayments of Federal Home Loan Bank advances, net	(250,000)	(290,000)
Payment of contingent consideration	(22,285)	(6,925)
(Decrease)/increase in securities sold under agreements to repurchase	(209,363)	5,189
Increase/(decrease) in bank deposits, net	1,067,420	(1,026,967)
(Decrease)/increase in securities loaned	(520,982)	124,707
Tax payments related to shares withheld for stock-based compensation plans	(70,754)	(30,425)
Proceeds from preferred stock issuance, net	217,995	154,988
Proceeds from issuance of senior notes, net	393,940
Proceeds from non-controlling interests		26,800
Repurchase of common stock	(56,517)	(180,434)
Cash dividends on preferred stock	(18,972)	(12,476)
Cash dividends paid to common stock and equity-award holders	(34,800)	(31,697)
Cash paid to employees upon settlement of equity awards	(27,101)
Other		(2,379)
Net cash provided by/(used in) financing activities	468,581	(1,332,429)
Effect of exchange rate changes on cash	(2,032)	(5,198)
Increase/(decrease) in cash, cash equivalents, and cash segregated for regulatory purposes	596,974	(1,137,854)
Cash, cash equivalents, and cash segregated for regulatory purposes at beginning of period	1,273,970	2,069,374
Cash, cash equivalents, and cash segregated for regulatory purposes at end of period	1,870,944	931,520
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds	112,190	110,907
Cash paid for interest	66,974	149,984
Noncash financing activities:
Unit grants, net of forfeitures	$ 117,801	$ 128,539