Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues:
Commissions		$ 749,536	$ 674,418	$ 640,287
Principal transactions		389,319	409,823	408,954
Investment banking		503,052	578,689	457,736
Asset management and service fees		493,761	386,001	305,639
Interest		179,101	185,969	142,539
Other income		62,224	14,785	64,659
Total revenues		2,376,993	2,249,685	2,019,814
Interest expense		45,399	41,261	46,368
Net revenues	[1]	2,331,594	2,208,424	1,973,446
Non-interest expenses:
Compensation and benefits		1,568,862	1,403,932	1,311,386
Occupancy and equipment rental		207,465	169,040	158,268
Communications and office supplies		130,678	106,926	99,726
Commissions and floor brokerage		42,518	36,555	37,225
Other operating expenses		240,504	201,177	181,612
Total non-interest expenses		2,190,027	1,917,630	1,788,217
Income from continuing operations before income tax expense		141,567	290,794	185,229
Provision for income taxes		49,231	111,664	12,322
Income from continuing operations		92,336	179,130	172,907
Discontinued operations:
Loss from discontinued operations, net of tax			(3,063)	(10,894)
Net income		$ 92,336	$ 176,067	$ 162,013
Earnings per basic common share
Income from continuing operations		$ 1.35	$ 2.69	$ 2.72
Income from discontinued operations			(0.04)	(0.17)
Earnings per basic common share		1.35	2.65	2.55
Earnings per diluted common share
Income from continuing operations		1.18	2.35	2.35
Income from discontinued operations			(0.04)	(0.15)
Earnings per diluted common share		$ 1.18	$ 2.31	$ 2.20
Weighted-average number of common shares outstanding:
Basic		68,543	66,472	63,568
Diluted		78,554	76,376	73,504

[1] No individual client accounted for more than 10 percent of total net revenues for the years ended December 31, 2015, 2014, and 2013.