Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount

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Taxes [Line Items]

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards classified as noncurrent.

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

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Estimated amount of loss resulting from an adverse tax position.

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The sum of the amounts of estimated penalties and interest recognized in the period arising from income tax examinations.

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

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The increase (decrease) during the reporting period in the account that represents the temporary difference that results from Income or Loss that is recognized for accounting purposes but not for tax purposes and vice versa.

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Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement.

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

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Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.

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Taxes - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended				9 Months Ended
Taxes - Additional Information (Detail) - USD ($)	Jul. 31, 2017	Jul. 31, 2017	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Jul. 31, 2017	Nov. 01, 2016	Oct. 31, 2016
Taxes [Line Items]
Statutory federal income tax rate		35.00%				35.00%
Deferred income taxes	$ 382,495,000	$ 382,495,000				$ 382,495,000		$ 281,926,000
Share-based compensation, excess tax benefit, amount		18,400,000				29,700,000
Fiscal year 2011, 2010, and 2009 \| California Franchise Tax Board
Taxes [Line Items]
Reduction in deferred tax asset due to tax settlement					$ 4,900,000
Unrecognized tax benefits decrease resulting from settlement					10,300,000
Deferred tax asset, increase (decrease), amount					$ 5,400,000
Minimum
Taxes [Line Items]
Estimated potential decrease in underlying unrecognized tax benefits	0	0				0
Maximum
Taxes [Line Items]
Estimated potential decrease in underlying unrecognized tax benefits	15,000,000	15,000,000				$ 15,000,000
Accounting Standards Update 2016-09 \| New Accounting Pronouncement, Early Adoption, Effect
Taxes [Line Items]
Deferred income taxes							$ 106,500,000
Retained Earnings \| Accounting Standards Update 2016-09 \| New Accounting Pronouncement, Early Adoption, Effect
Taxes [Line Items]
Cumulative effect adjustment							$ 106,500,000
Foreign Tax Authority \| Fiscal years 2012 to 2016 \| KOREA, REPUBLIC OF
Taxes [Line Items]
Tax adjustments, settlements expense (benefit)		7,900,000
Foreign Tax Authority \| Fiscal Year 2014 \| KOREA, REPUBLIC OF
Taxes [Line Items]
Tax adjustments, settlements expense (benefit)		$ (10,900,000)
Foreign Tax Authority \| Fiscal Year 2011 \| TAIWAN, PROVINCE OF CHINA
Taxes [Line Items]
Unrecognized tax benefits decrease resulting from settlement			$ 700,000
Income Taxes Paid			$ 300,000
Foreign Tax Authority \| Fiscal years 2010 to 2015 \| India Taxing Authority
Taxes [Line Items]
Tax adjustments, settlements expense (benefit)				$ 2,400,000
Synopsys Hungary \| Foreign Tax Authority \| Tax Year 2011 - Tax Year 2013 \| Hungarian Tax Authority
Taxes [Line Items]
Estimate of tax assessment	47,000,000
Estimate of additional penalties and interest	18,000,000
Synopsys Hungary \| Foreign Tax Authority \| Fiscal Year 2015 and Beyond \| Hungarian Tax Authority
Taxes [Line Items]
Estimate of tax assessment	$ 18,000,000