Consolidated Statements Of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues:
Commissions		$ 182,104	$ 183,771	$ 380,034	$ 364,073
Principal transactions		126,426	85,542	247,374	186,275
Investment banking		133,125	161,007	233,783	285,568
Asset management and service fees		144,567	119,936	289,099	233,805
Interest		65,780	43,852	128,607	86,588
Other income		17,405	13,741	24,595	25,541
Total revenues		669,407	607,849	1,303,492	1,181,850
Interest expense		17,262	10,098	31,373	23,117
Net revenues	[1]	652,145	597,751	1,272,119	1,158,733
Non-interest expenses:
Compensation and benefits		460,023	409,998	871,136	765,691
Occupancy and equipment rental		58,746	48,346	116,002	92,516
Communications and office supplies		37,426	31,114	74,086	60,348
Commissions and floor brokerage		12,145	9,124	23,876	19,193
Other operating expenses		68,012	61,098	127,313	112,848
Total non-interest expenses		636,352	559,680	1,212,413	1,050,596
Income from operations before income tax expense		15,793	38,071	59,706	108,137
Provision for income taxes		6,022	17,183	22,880	44,152
Net income		$ 9,771	$ 20,888	$ 36,826	$ 63,985
Earnings per common share:
Basic		$ 0.15	$ 0.31	$ 0.55	$ 0.94
Diluted		$ 0.13	$ 0.27	$ 0.48	$ 0.82
Weighted-average number of common shares outstanding:
Basic		66,792	68,370	67,186	68,189
Diluted		75,982	77,856	76,084	77,624

[1] No individual client accounted for more than 10 percent of total net revenues for the three and six months ended June 30, 2016 or 2015.