Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Commissions
U.S. high-grade	$ 108,931	$ 83,796	$ 62,557
Eurobond	17,799	18,656	20,339
Other	28,714	19,728	13,236
Total commissions	155,444	122,180	96,132
Technology products and services	14,310	13,648	9,778
Information and user access fees	7,199	6,681	6,252
Investment income	1,229	1,192	1,222
Other	2,917	2,527	1,055
Total revenues	181,099	146,228	114,439
Expenses
Employee compensation and benefits	58,786	56,446	50,274
Depreciation and amortization	6,781	6,350	6,790
Technology and communications	10,912	9,982	8,436
Professional and consulting fees	10,138	8,503	6,869
Occupancy	2,921	2,997	3,129
Marketing and advertising	4,882	3,075	2,882
General and administrative	7,946	7,965	6,010
Total expenses	102,366	95,318	84,390
Income before income taxes	78,733	50,910	30,049
Provision for income taxes	31,029	19,482	13,947
Net income	$ 47,704	$ 31,428	$ 16,102
Net income per common share
Basic	$ 1.29	$ 0.86	$ 0.44
Diluted	$ 1.20	$ 0.80	$ 0.42
Cash dividends declared per common share	$ 0.36	$ 0.28	$ 0.07
Weighted average shares outstanding
Basic	37,006	33,159	33,264
Diluted	39,608	39,051	38,082