Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Revenues:
Commissions	$ 123,303		$ 155,786
Principal transactions	116,233		92,859
Investment banking	70,438		41,418
Asset management and service fees	60,818		57,680
Interest	25,257		18,856
Other income	13,294		6,256
Total revenues	409,343		372,855
Interest expense	9,010		6,242
Net revenues	400,333	[1]	366,613	[1]
Non-interest expenses:
Compensation and benefits	254,704		231,166
Occupancy and equipment rental	30,791		29,325
Communications and office supplies	20,373		18,845
Commissions and floor brokerage	7,612		6,649
Other operating expenses	27,599		29,944
Total non-interest expenses	341,079		315,929
Income before income tax expense	59,254		50,684
Provision for income taxes	24,481		19,286
Net income	$ 34,773		$ 31,398
Earnings per common share:
Basic	$ 0.65		$ 0.60
Diluted	$ 0.55	[2]	$ 0.50	[2]
Weighted average number of common shares outstanding:
Basic	53,243		52,534
Diluted	62,669		63,179

[1] No individual client accounted for more than 10 percent of total net revenues for the three months ended March 31, 2012 or 2011.

[2] Diluted earnings per share is computed on the basis of the weighted average number of shares of common stock plus the effect of dilutive potential common shares outstanding during the period using the treasury stock method. Diluted earnings per share include stock options and units.