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	$ 174,199	$ 155,444	$ 122,180
Technology products and services	12,351	14,310	13,648
Information and user access fees	7,435	7,199	6,681
Investment income	1,058	1,229	1,192
Other	3,161	2,917	2,527
Total revenues	198,204	181,099	146,228
Expenses
Employee compensation and benefits	60,361	58,786	56,446
Depreciation and amortization	8,233	6,781	6,350
Technology and communications	12,766	10,912	9,982
Professional and consulting fees	13,081	10,138	8,503
Occupancy	3,012	2,921	2,997
Marketing and advertising	5,470	4,882	3,075
General and administrative	8,595	7,946	7,965
Total expenses	111,518	102,366	95,318
Income before income taxes	86,686	78,733	50,910
Provision for income taxes	26,617	31,029	19,482
Net income	$ 60,069	$ 47,704	$ 31,428
Net income per common share
Basic	$ 1.65	$ 1.29	$ 0.86
Diluted	$ 1.59	$ 1.20	$ 0.80
Cash dividends declared per common share	$ 1.74	$ 0.36	$ 0.28
Weighted average shares outstanding
Basic	36,516	37,006	33,159
Diluted	37,816	39,608	39,051