Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows From Operating Activities:
Net income	$ 563,468	$ 315,003
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	33,496	29,659
Amortization of loans and advances to financial advisors and other employees	83,850	76,728
Amortization of premium on investment portfolio	12,969	15,516
Provision for credit losses and allowance for loans and advances to financial advisors and other employees	(15,564)	35,066
Amortization of intangible assets	13,216	14,489
Deferred income taxes	(42,492)	(8,973)
Stock-based compensation	85,283	80,987
Losses on sale of investments	1,302	22,828
Other, net	39,809	(7,926)
Receivables:
Brokerage clients	(185,327)	297,127
Brokers, dealers, and clearing organizations	61,063	183,105
Securities purchased under agreements to resell	(380,605)	(51,852)
Financial instruments owned, including those pledged	(505,358)	153,217
Loans originated as held for sale	(1,594,937)	(2,013,038)
Proceeds from mortgages held for sale	1,954,135	2,141,691
Loans and advances to financial advisors and other employees	(94,958)	(138,020)
Other assets	(76,967)	64,572
Increase/(decrease) in operating liabilities, net of liabilities assumed:
Brokerage clients	253,308	287,384
Brokers, dealers, and clearing organizations	28,900	(33,956)
Drafts	(31,848)	(29,060)
Financial instruments sold, but not yet purchased	283,050	(62,918)
Other liabilities and accrued expenses	84,942	(37,105)
Net cash provided by operating activities	570,735	1,334,524
Net cash provided by operating activities	570,735	1,334,524
Cash Flows From Investing Activities:
Principal paydowns, calls, and maturities of available-for-sale securities	448,780	781,922
Calls and principal paydowns of held-to-maturity securities	1,307,342	155,784
Sale or maturity of investments	17,581	2,252
Disposition of business		37,000
Increase in loans held for investment, net	(2,480,035)	(1,075,568)
Payments for:
Purchase of fixed assets	(173,183)	(70,532)
Purchase of available-for-sale securities	(807,088)	(628,660)
Purchase of held-to-maturity securities	(2,223,971)	(384,700)
Purchase of investments	(20,515)	(21,317)
Acquisitions, net of cash received	(315)	(280)
Net cash used in investing activities	(3,931,404)	(1,204,099)
Cash Flows From Financing Activities:
Proceeds from/(repayments of) Federal Home Loan Bank advances, net	52,000	(250,000)
Payment of contingent consideration	(16,798)	(22,285)
Increase/(decrease) in securities sold under agreements to repurchase	4,496	(209,363)
Increase in bank deposits, net	3,002,377	1,067,420
Increase/(decrease) in securities loaned	38,441	(520,982)
Tax payments related to shares withheld for stock-based compensation plans	(70,202)	(70,754)
Proceeds from preferred stock issuance, net	290,721	217,995
Proceeds from issuance of senior notes, net		393,940
Redemption of preferred stock	(150,000)
Repurchase of common stock	(84,723)	(56,517)
Cash dividends on preferred stock	(26,267)	(18,972)
Cash dividends paid to common stock and equity-award holders	(47,307)	(34,800)
Cash paid to employees upon settlement of equity awards		(27,101)
Net cash provided by financing activities	2,992,738	468,581
Effect of exchange rate changes on cash	(3,907)	(2,032)
Increase/(decrease) in cash, cash equivalents, and cash segregated for regulatory purposes	(371,838)	596,974
Cash, cash equivalents, and cash segregated for regulatory purposes at beginning of period	2,452,206	1,273,970
Cash, cash equivalents, and cash segregated for regulatory purposes at end of period	2,080,368	1,870,944
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds	227,641	112,190
Cash paid for interest	47,070	66,974
Noncash financing activities:
Unit grants, net of forfeitures	$ 142,771	$ 117,801