Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash Flows From Operating Activities:
Net income	$ 86,589	$ 99,439
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	9,378	10,290
Amortization of loans and advances to financial advisors and other employees	27,729	21,596
Amortization of premium on investment portfolio	6,210	8,727
Provision for loan losses and allowance for loans and advances to financial advisors and other employees	19,253	1,611
Amortization of intangible assets	5,032	3,593
Deferred income taxes	17,098	2,102
Stock-based compensation	30,762	32,119
(Gains)/losses on sale of investments	31,043	(2,174)
Other, net	(5,464)	(6,429)
Receivables:
Brokerage clients	(117,920)	(182,761)
Brokers, dealers, and clearing organizations	(76,604)	(72,766)
Securities purchased under agreements to resell	(73,960)	131,866
Financial instruments owned, including those pledged	40,421	2,641
Loans originated as held for sale	(474,824)	(272,301)
Proceeds from mortgages held for sale	506,936	333,478
Loans and advances to financial advisors and other employees	(40,554)	(50,216)
Other assets	(51,427)	(24,357)
Increase/(decrease) in operating liabilities, net of liabilities assumed:
Brokerage clients	205,936	(200,229)
Brokers, dealers, and clearing organizations	106,196	21,639
Drafts	(29,019)	(4,263)
Financial instruments sold, but not yet purchased	5,943	31,754
Other liabilities and accrued expenses	(234,445)	(252,199)
Net cash used in operating activities	(5,691)	(366,840)
Cash Flows From Investing Activities:
Principal paydowns, sales, calls, and maturities of available-for-sale securities	385,131	93,349
Calls and principal paydowns of held-to-maturity securities	155,184	114,535
Sale or maturity of investments	2,252
Disposition of business	37,000
Increase in loans held for investment, net	(593,296)	(195,186)
Payments for:
Purchase of available-for-sale securities	(601,660)	(250)
Purchase of held-to-maturity securities	(384,700)
Purchase of fixed assets	(53,002)	(72,868)
Purchase of investments	(12,900)
Acquisitions, net of cash received		(28,523)
Net cash used in investing activities	(1,065,991)	(88,943)
Cash Flows From Financing Activities:
Proceeds from borrowings, net	198,000	218,315
Repayments of Federal Home Loan Bank advances, net		(290,000)
Payment of contingent consideration	(2,208)	(2,994)
Increase/(decrease) in securities sold under agreements to repurchase	83,894	(93,419)
Increase/(decrease) in bank deposits, net	1,548,352	(813,736)
Increase/(decrease) in securities loaned	(272,560)	132,952
Tax payments related to shares withheld for stock-based compensation plans	(68,497)	(27,847)
Proceeds from preferred stock issuance, net		155,294
Proceeds from non-controlling interests		26,800
Repurchase of common stock	(56,160)	(53,869)
Cash dividends on preferred stock	(4,844)	(2,344)
Cash dividends paid to common stock and equity-award holders	(11,472)	(12,944)
Cash paid to employees upon settlement of equity awards	(27,101)
Other		(490)
Net cash provided by/(used in) financing activities	1,387,404	(764,282)
Effect of exchange rate changes on cash	(9,822)	2,156
Increase/(decrease) in cash, cash equivalents, and cash segregated for regulatory purposes	305,900	(1,217,909)
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	1,579,870	851,465
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds	15,423	466
Cash paid for interest	28,707	49,425
Noncash financing activities:
Unit grants, net of forfeitures	$ 106,522	$ 92,344