Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues
Commissions	$ 86,239	$ 66,412	$ 165,332	$ 133,430
Information and post-trade services	8,586	7,632	16,365	15,311
Investment income	517	190	935	373
Other	1,297	1,257	2,580	3,148
Total revenues	96,639	75,491	185,212	152,262
Expenses
Employee compensation and benefits	25,815	20,593	50,342	41,767
Depreciation and amortization	4,540	4,603	9,221	9,215
Technology and communications	4,277	3,967	8,581	8,305
Professional and consulting fees	4,245	3,011	8,107	6,293
Occupancy	1,225	1,232	2,386	2,224
Marketing and advertising	1,824	1,764	3,602	2,956
General and administrative	4,162	3,262	8,052	5,941
Total expenses	46,088	38,432	90,291	76,701
Income before income taxes	50,551	37,059	94,921	75,561
Provision for income taxes	17,425	12,821	32,832	26,730
Net income	$ 33,126	$ 24,238	$ 62,089	$ 48,831
Net income per common share
Basic	$ 0.90	$ 0.66	$ 1.69	$ 1.33
Diluted	0.88	0.64	1.65	1.30
Cash dividends declared per common share	$ 0.26	$ 0.20	$ 0.52	$ 0.40
Weighted average shares outstanding
Basic	36,876	36,699	36,826	36,703
Diluted	37,748	37,642	37,710	37,634