Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash Flows From Operating Activities:
Net income	$ 92,336	$ 176,067	$ 162,013
Adjustments to reconcile net income to net cash provided by/(used in) operating activities:
Depreciation and amortization	36,715	29,280	33,988
Amortization of loans and advances to financial advisors and other employees	53,913	64,735	64,930
Amortization of premium on investment portfolio	2,750	5,847	8,321
Provision for loan losses and allowance for loans and advances to financial advisors and other employees	14,694	9,713	10,618
Amortization of intangible assets	10,423	12,366	12,131
Deferred income taxes	(2,578)	5,256	(26,389)
Excess tax benefits from stock-based compensation	(14,741)	(19,858)	(12,018)
Stock-based compensation	165,641	94,006	137,447
Losses on sale of investments	9,255	22	13,319
Gain on acquisition			(7,566)
Other, net	(13,159)	(9,778)	(3,640)
Decrease/(increase) in operating assets, net of assets acquired:
Cash segregated for regulatory purposes	(178,081)	(45,343)	128,142
Receivables:
Brokerage clients, net	(1,003,257)	58,917	(42,627)
Brokers, dealers, and clearing organizations	82,960	(263,391)	(30,634)
Securities purchased under agreements to resell	(105,345)	169,997	(66,380)
Financial instruments owned, including those pledged	90,716	26,280	70,053
Loans originated as held for sale	(1,855,714)	(1,132,671)	(1,275,647)
Proceeds from mortgages held for sale	1,814,168	1,112,318	1,372,552
Loans and advances to financial advisors and other employees	(187,234)	(79,216)	(71,857)
Other assets	100,670	(2,509)	79,662
Increase/(decrease) in operating liabilities, net of liabilities assumed:
Brokerage clients	678,926	2,554	23,433
Brokers, dealers, and clearing organizations	98,301	(8,198)	3,976
Drafts	108,659	488	(15,723)
Financial instruments sold, but not yet purchased	(65,521)	106,051	85,127
Other liabilities and accrued expenses	(261,326)	(62,664)	48,988
Net cash provided by/(used in) operating activities	(326,829)	250,269	702,219
Cash Flows From Investing Activities:
Sale of bank foreclosed assets	75
Increase in bank loans, net	(517,563)	(668,354)	(249,018)
Payments for:
Purchase of available-for-sale securities	(991,954)	(416,851)	(1,314,290)
Purchase of held-to-maturity securities	(802,668)	(7,959)	(16,438)
Purchase of investments	(45,151)	(48,834)	(71,777)
Purchase of fixed assets	(69,822)	(26,632)	(32,278)
Acquisitions, net of cash acquired	(604,659)	(80,378)	(88,592)
Net cash used in investing activities	(1,973,265)	(392,936)	(1,106,274)
Maturities, calls, sales, and principal paydowns of available-for-sale securities	866,899	698,895	435,827
Calls and principal paydowns of held-to-maturity securities	126,258	96,618	93,703
Sale or maturity of investments	65,320	60,428	90,265
Sale of aircraft			45,951
Sale of other real estate owned		131	373
Cash Flows from Financing Activities:
Repayments of short-term borrowings	(126,637)	(55,700)	(249,000)
Proceeds from issuance of senior notes, net	297,042	295,638
Increase/(decrease) in securities sold under agreements to repurchase	239,494	(224,629)	123,463
Increase in bank deposits, net	1,848,275	126,758	881,794
Increase/(decrease) in securities loaned	325,707	(35,914)	20,948
Excess tax benefits from stock-based compensation	14,741	19,858	12,018
Issuance of common stock for stock option exercises	660	317	650
Proceeds from advances from the Federal Home Loan Bank	148,000
Repurchase of common stock	(117,752)		(13,670)
Repayment of non-recourse debt			(58,992)
Repayment of Senior Notes	(175,000)
Contingent consideration	(29,598)
Extinguishment of subordinated debt		(3,131)	(2,187)
Net cash provided by financing activities	2,424,932	123,197	715,024
Effect of exchange rate changes on cash	(3,601)	(7,308)	1,650
Increase/(decrease) in cash and cash equivalents	121,237	(26,778)	312,619
Cash and cash equivalents at beginning of year	689,782	716,560	403,941
Cash and cash equivalents at end of year	811,019	689,782	716,560
Supplemental disclosure of cash flow information:
Cash paid for interest	41,801	40,471	46,360
Cash paid for income taxes, net of refunds	59,356	107,009	5,803
Noncash investing and financing activities:
Unit grants, net of forfeitures	267,769	190,003	228,230
Issuance of common stock for acquisitions	80,981	$ 19,183	265,066
Shares surrendered into treasury	$ 223
Stone & Youngberg contingent earn-out			$ 3,266