Supplementary Data - Selected Unaudited Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 587,159	$ 555,805	$ 557,204	$ 542,043	$ 539,012	$ 521,812	$ 517,697	$ 478,951	$ 2,242,211	$ 2,057,472	$ 1,962,214
Gross margin	447,315	426,334	432,232	417,410	417,591	406,282	403,612	373,102	1,723,291	1,600,587	1,508,662
Income before provision for income taxes	55,918	65,193	83,884	76,615	62,128	70,771	68,059	71,184	$ 281,610	$ 272,142	$ 275,666
Net income	$ 49,762	$ 55,387	$ 55,596	$ 65,189	$ 62,455	$ 65,656	$ 63,317	$ 67,696
Net income per share
Basic (in USD per share)	$ 0.32	$ 0.36	$ 0.36	$ 0.42	$ 0.40	$ 0.42	$ 0.41	$ 0.44	$ 1.46	$ 1.67	$ 1.62
Diluted (in USD per share)	$ 0.31	$ 0.35	$ 0.35	$ 0.41	$ 0.39	$ 0.42	$ 0.40	$ 0.43	$ 1.43	$ 1.64	$ 1.58

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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