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Stock Compensation - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Jul. 31, 2018 | Jul. 31, 2017 | Jul. 31, 2018 | Jul. 31, 2017 | Jan. 31, 2017
New Accounting Pronouncement, Early Adoption [Line Items] |  |  |  |  |
Share-based compensation, excess tax benefit, amount | $ 14.6 | $ 18.4 | $ 25.4 | $ 29.7 |
Unamortized share-based compensation expense | $ 280.8 |  | $ 280.8 |  |
Weighted-average period of total compensation costs to be recognized in years |  |  | 2 years 6 months |  |
Other Assumed Stock Plans |  |  |  |  |
New Accounting Pronouncement, Early Adoption [Line Items] |  |  |  |  |
Share based compensation arrangement assumed stock plans remaining outstanding shares (in shares) |  |  |  |  | 0.4

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- Definition Unrecognized cost of unvested share-based compensation awards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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