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Unrecognized Tax Benefits, Income Tax Expense

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

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- Definition

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

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The amount of the additional liability or refund received or expected based on a final settlement with a taxing authority.

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

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

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Income Taxes - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended			9 Months Ended
	Jul. 31, 2017	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2021	Jul. 31, 2018
Taxes [Line Items]
Statutory federal income tax rate					21.00%
Minimum
Taxes [Line Items]
Estimated potential decrease in underlying unrecognized tax benefits		$ 0			$ 0
Maximum
Taxes [Line Items]
Estimated potential decrease in underlying unrecognized tax benefits		48,000,000			$ 48,000,000
California Franchise Tax Board \| Tax Year 2015 - Tax Year 2017
Taxes [Line Items]
Decrease in unrecognized tax benefits resulting from settlement with taxing authorities		$ 19,200,000
Synopsys Hungary \| Foreign Tax Authority \| Tax Year 2011 - Tax Year 2013 \| Hungarian Tax Authority
Taxes [Line Items]
Aggregate tax assessment						$ 25,000,000
Estimate of additional penalties and interest	$ 11,000,000
Unrecognized tax benefits				$ 17,400,000
Synopsys Hungary \| Foreign Tax Authority \| Tax Year 2014 - Tax Year 2018 \| Hungarian Tax Authority
Taxes [Line Items]
Unrecognized tax benefits from settlement with tax authorities			$ 6,900,000