Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash Flows From Operating Activities:
Net income	$ 27,055	$ 43,097
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	10,629	7,952
Amortization of loans and advances to financial advisors and other employees	18,995	15,769
Amortization of premium on investment portfolio	1,622	1,192
Provision for loan losses and allowance for loans and advances to financial advisors and other employees	4,571	2,200
Amortization of intangible assets	2,974	1,942
Deferred income taxes	72,979	49,469
Excess tax benefits/(tax deficit) from stock-based compensation	4,215	(11,768)
Stock-based compensation	30,450	22,356
(Gains)/losses on sale of investments	3,826	(5,669)
Other, net	(2,524)	3,382
Decrease/(increase) in operating assets, net of assets acquired:
Cash segregated for regulatory purposes and restricted cash	190,676	49,519
Receivables:
Brokerage clients	216,856	(58,082)
Brokers, dealers, and clearing organizations	(117,959)	200,414
Securities purchased under agreements to resell	(47,523)	(143,534)
Financial instruments owned, including those pledged	(279,338)	(24,309)
Loans originated as held for sale	(419,601)	(464,087)
Proceeds from mortgages held for sale	472,886	394,751
Loans and advances to financial advisors and other employees	(25,417)	(10,782)
Other assets	(133,412)	(32,614)
Increase/(decrease) in operating liabilities, net of liabilities assumed:
Brokerage clients	76,992	10,791
Brokers, dealers, and clearing organizations	(3,792)	(1,624)
Drafts	(109,354)	(20,357)
Financial instruments sold, but not yet purchased	153,097	(42,384)
Other liabilities and accrued expenses	(246,487)	(288,049)
Net cash used in operating activities	(97,584)	(300,425)
Cash Flows From Investing Activities:
Maturities and principal paydowns of available-for-sale securities	31,303	72,290
Calls and principal paydowns of held-to-maturity securities	37,577	23,186
Sale or maturity of investments	12,978	35,858
Increase in bank loans, net	(327,931)	(190,183)
Payments for:
Purchase of available-for-sale securities	(529,707)	(199)
Purchase of held-to-maturity securities	(210,677)
Purchase of investments	(1,313)	(19,262)
Purchase of fixed assets	(9,270)	(20,996)
Acquisitions, net of cash acquired	(68,680)	(961)
Net cash used in investing activities	(1,065,720)	(100,267)
Cash Flows From Financing Activities:
Proceeds from borrowings	238,497	20,500
Proceeds from Federal Home Loan Bank advances	352,000
Increase in securities sold under agreements to repurchase	12,055	216,678
Increase in bank deposits, net	579,744	43,959
Increase/(decrease) in securities loaned	(151,319)	442
Excess tax benefits/(tax deficit) from stock-based compensation	(4,215)	11,768
Issuance of common stock for stock option exercises	175	200
Repurchase of common stock	(95,116)
Repayment of senior notes		(175,000)
Net cash provided by financing activities	931,821	118,547
Effect of exchange rate changes on cash	(2,186)	(3,881)
Decrease in cash and cash equivalents	(233,669)	(286,026)
Cash and cash equivalents at beginning of period	811,019	689,782
Cash and cash equivalents at end of period	577,350	403,756
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds	20,061	30,936
Cash paid for interest	13,630	10,135
Noncash financing activities:
Unit grants, net of forfeitures	98,876	53,045
Issuance of common stock for acquisitions	$ 11,427
Shares surrendered into treasury		$ 223