Estimated Future Amortization of Intangible Assets (Parenthetical) (Detail)	Apr. 30, 2013 Y
Expected Amortization Expense [Line Items]
Estimated completion period of IPR&D projects, years	2

Estimated completion period of in process research and development projects.

No definition available.

Name:	snps_EstimatedCompletionPeriodOfInProcessResearchAndDevelopmentProjects
Namespace Prefix:	snps_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	instant