v2.4.0.6

Employee Benefit Plans (Equity Compensation Plans - 2006 Employee Equity Incentive Plan) (Narrative) (Details)									0 Months Ended
	Oct. 31, 2011 years		Oct. 31, 2010 years		Oct. 31, 2009 years		Oct. 31, 2008 years		Mar. 24, 2011 2006 Employee Equity Incentive Plan [Member]	Oct. 31, 2011 2006 Employee Equity Incentive Plan [Member]	Oct. 31, 2011 All Stock Plans [Member]	Oct. 31, 2010 All Stock Plans [Member]	Oct. 31, 2009 All Stock Plans [Member]	Oct. 31, 2008 All Stock Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional reserved for future issuance under the 2006 Employee Plan									7.0
Weighted-average remaining contractual life (in years)	2.97		2.80		2.89		3.43			7
Aggregate stock options outstanding											15,960,000	21,184,000	25,818,000	28,777,000
Shares available for future grant	5,911,000	[1]	2,606,000	[1]	6,703,000	[1]	4,347,000	[1]
Number of shares available contingent upon cancellation or expiration of prior plans										6,400,000
[1] Excluding shares reserved for future issuance under the 2005 Directors Plan.

X

- Definition

Number of shares available contingent upon cancellation expiration of prior plans.

+ References

No definition available.

+ Details

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Namespace Prefix:	snps_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Sets forth the nature of any other increase or decrease in the number of shares reserved for issuance under the option plan.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a)

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(b)

-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 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The weighted average period between the balance sheet date and expiration for all awards outstanding under the plan, which may be expressed in a decimal value for number of years.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Section 50

-Paragraph 2

-Subparagraph (e)(1)

-SubTopic 10

-Topic 718

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant