v2.4.0.6

Employee Benefit Plans (Employee Stock Purchase Plan) (Narrative) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2009
Employee Benefit Plans [Abstract]
Threshold for employee stock purchases under ESPP, maximum value	85.00%
ESPP offering period (in years)	2
Shares issued	2.2	2.5	2.5
Weighted average purchase price of stock purchased	$ 17.95	$ 15.32	$ 15.55
Shares reserved for future issuance under the ESPP	2.8

X

- Definition

Share-based compensation arrangement by share-based payment award, offering period

+ References

No definition available.

+ Details

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X

- Definition

The number of shares reserved for issuance under the employee stock purchase plan.

+ References

No definition available.

+ Details

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X

- Definition

Threshold for granted rights for fair value of employees stock purchases under the employee stock purchase plan.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The weighted-average purchase price of stock purchased under the employee stock purchase plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	snps_
Data Type:	num:perShareItemType
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Period Type:	instant

X

- Details

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X

- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3



Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 5

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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