Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Revenues:
Commissions	$ 512,976		$ 561,081		$ 445,260
Principal transactions	408,484		343,213		453,533
Investment banking	286,585		199,584		218,104
Asset management and service fees	257,981		228,834		193,159
Interest	109,776		89,466		65,326
Other income	70,231		19,731		19,855
Total revenues	1,646,033		1,441,909		1,395,237
Interest expense	33,383		25,347		13,211
Net revenues	1,612,650		1,416,562		1,382,026
Non-interest expenses:
Compensation and benefits	1,023,943		900,421		1,056,202
Occupancy and equipment rental	130,247		121,929		115,742
Communications and office supplies	80,941		75,589		69,929
Commissions and floor brokerage	30,870		27,040		26,301
Other operating expenses	120,777		152,975		114,081
Total non-interest expenses	1,386,778		1,277,954		1,382,255
Income before income tax expense	225,872		138,608		(229)
Provision for income taxes	87,299		54,474		(2,136)
Net income	$ 138,573		$ 84,134		$ 1,907
Earnings per common share:
Basic	$ 2.59		$ 1.61		$ 0.04
Diluted	$ 2.20	[1]	$ 1.33	[1]	$ 0.03	[1]
Weighted average number of common shares outstanding:
Basic	53,563		52,418		48,723
Diluted	62,937		63,058		57,672

[1] 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.