Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues
Commissions	$ 47,186	$ 44,902
Technology products and services	3,139	2,908
Information and post-trade services	3,703	1,871
Investment income	132	303
Other	1,397	751
Total revenues	55,557	50,735
Expenses
Employee compensation and benefits	16,353	15,841
Depreciation and amortization	2,569	1,854
Technology and communications	3,191	2,955
Professional and consulting fees	4,601	3,024
Occupancy	932	759
Marketing and advertising	985	1,447
General and administrative	2,613	2,107
Total expenses	31,244	27,987
Income before income taxes	24,313	22,748
Provision for income taxes	8,987	9,255
Net income	$ 15,326	$ 13,493
Net income per common share
Basic	$ 0.42	$ 0.37
Diluted	$ 0.41	$ 0.35
Cash dividends declared per common share	$ 0.13	$ 0.11
Weighted average common shares
Basic	36,774	36,934
Diluted	37,673	38,695