Income Tax Rate Reconciliation, Estimated Research Tax Credit Benefit, Amount

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- Definition

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of (increase) decrease reasonably possible in the estimated lower bound of the unrecognized tax benefit for a tax position taken or expected to be taken.

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Amount of (increase) decrease reasonably possible in the estimated upper bound of the unrecognized tax benefit for a tax position taken or expected to be taken.

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- Definition

Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Oct. 31, 2015
Taxes [Line Items]
Statutory federal income tax rate	35.00%
Gross unrecognized tax benefits	$ 126.1us-gaap_UnrecognizedTaxBenefits
Unrecognized tax benefits that would affect effective tax rate	122.5
Estimated potential decrease in underlying unrecognized tax benefits, minimum	0
Estimated potential decrease in underlying unrecognized tax benefits, maximum	31
IRS \| Fiscal Year 2012
Taxes [Line Items]
Unrecognized tax benefits decrease resulting from settlement		10.0
Taiwan \| Fiscal Year 2012
Taxes [Line Items]
Unrecognized tax benefits decrease resulting from settlement	1.1
Forecast
Taxes [Line Items]
Expected research tax credit benefit			$ 12.4