Selected Quarterly Financial Data (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2010	Apr. 30, 2010	Jan. 31, 2010	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2010
Selected Quarterly Financial Data [Unaudited]
Net Revenues	$ 176,052	$ 172,302	$ 163,388	$ 149,919	$ 151,297	$ 148,029	$ 137,658	$ 121,658	$ 126,596	$ 121,719	$ 110,447	$ 99,262	$ 661,661	$ 558,642	$ 458,024
Gross Profit	87,246	86,049	79,479	71,243	74,914	73,432	65,639	56,804	62,966	61,630	53,668	47,508	324,017	270,789	225,772
Net Income	$ 12,889	$ 12,596	$ 9,306	$ 7,365	$ 10,476	$ 10,081	$ 7,817	$ 7,985	$ 8,577	$ 8,013	$ 5,787	$ 4,005	$ 42,156	$ 36,359	$ 26,381
Net Income Per Share - Basic (in dollars per share)	$ 0.47	$ 0.45	$ 0.34	$ 0.26	$ 0.37	$ 0.36	$ 0.28	$ 0.29	$ 0.31	$ 0.29	$ 0.21	$ 0.14	$ 1.52	$ 1.30	$ 0.95
Net Income Per Share - Diluted (in dollars per share)	$ 0.46	$ 0.45	$ 0.33	$ 0.26	$ 0.37	$ 0.36	$ 0.28	$ 0.28	$ 0.31	$ 0.29	$ 0.21	$ 0.14	$ 1.51	$ 1.29	$ 0.94
Weighted Average Common Shares Outstanding (in shares)	27,705,000	27,695,000	27,685,000	27,888,000	27,949,000	27,941,000	27,920,000	27,884,000	27,835,000	27,815,000	27,772,000	27,723,000	27,742,257	27,971,100	27,786,083
Weighted Average Common Shares Outstanding - Diluted (in shares)	27,906,000	27,888,000	27,878,000	28,041,000	28,138,000	28,147,000	28,142,000	28,122,000	28,087,000	28,098,000	28,077,000	28,022,000	27,920,920	28,207,358	28,038,304