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Fair Value Measures - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Oct. 31, 2014
Oct. 31, 2012
Oct. 31, 2013
Fair Value Measures [Line Items]      
Contingent consideration     $ 0.5us-gaap_BusinessCombinationContingentConsiderationLiability
Other-than-temporary impairment   0.5us-gaap_CostmethodInvestmentsOtherThanTemporaryImpairment  
Non-marketable equity securities 10.9us-gaap_SecuritiesOwnedNotReadilyMarketable   11.5us-gaap_SecuritiesOwnedNotReadilyMarketable
Proceeds from Sale, Maturity and Collection of Investments 7.1us-gaap_ProceedsFromSaleMaturityAndCollectionsOfInvestments    
Investment Owned, at Cost 0.2us-gaap_InvestmentOwnedAtCost    
Cost Method Investments      
Fair Value Measures [Line Items]      
Non-marketable equity securities 6.7us-gaap_SecuritiesOwnedNotReadilyMarketable
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CostmethodInvestmentsMember
  6.9us-gaap_SecuritiesOwnedNotReadilyMarketable
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_CostmethodInvestmentsMember
Equity Method Investments      
Fair Value Measures [Line Items]      
Non-marketable equity securities 4.2us-gaap_SecuritiesOwnedNotReadilyMarketable
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_EquityMethodInvestmentsMember
  4.6us-gaap_SecuritiesOwnedNotReadilyMarketable
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_EquityMethodInvestmentsMember
Other Income Expense Net      
Fair Value Measures [Line Items]      
Gain from liquidation of investment $ 6.9us-gaap_GainOnSaleOfInvestments
/ us-gaap_IncomeStatementLocationAxis
= snps_OtherIncomeExpenseNetMember