Agreed consideration for securities litigation settlement.

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Namespace Prefix:	cdns
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Plaintiff's attorneys fees paid by Company's insurers as part of derivative settlement.

+ Details

Name:	cdns_AttorneysFeePaidToPlaintiffCounselByThirdParty
Namespace Prefix:	cdns
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Company portion of accrued interest for securities litigation settlement.

+ Details

Name:	cdns_CompanyPortionOfAccruedInterest
Namespace Prefix:	cdns
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Company portion of the securities litigation settlement consideration.

+ Details

Name:	cdns_CompanyPortionOfSettlementConsideration
Namespace Prefix:	cdns
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Consideration for securities litigation settlement paid by Company's insurers.

+ Details

Name:	cdns_ConsiderationForLitigationSettlementPaidByCompanysInsurers
Namespace Prefix:	cdns
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Consideration for proposed securities litigation settlement to be paid by Company's insurers.

+ Details

Name:	cdns_ConsiderationForLitigationSettlementToBePaidByThirdParty
Namespace Prefix:	cdns
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Payment to securities litigation settlement fund.

+ Details

Name:	cdns_PaymentForSettlementFund
Namespace Prefix:	cdns
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Remaining consideration paid by Company's insurers for securities litigation settlement fund.

+ Details

Name:	cdns_RemainingConsiderationPaidByCompanysInsurersForLitigationSettlementFund
Namespace Prefix:	cdns
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_CommitmentsAndContingenciesDisclosureAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Describes the nature of the product warranty, including the approximate term of the product warranty, how the product warranty arose, and the events or circumstances that would require the warrantor to perform under the product warranty.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph 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 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Contingencies (Details Textual) (USD $) In Millions	3 Months Ended	6 Months Ended
Contingencies (Details Textual) (USD $) In Millions	Jul. 02, 2011	Jul. 02, 2011	Feb. 11, 2011	Feb. 08, 2011
Contingencies [Abstract]
Agreed consideration for securities litigation settlement			$ 38.0
Payment to securities litigation settlement fund	16.4
Company portion of the securities litigation settlement consideration	15.8
Company portion of accrued interest for securities litigation settlement	0.6
Consideration for securities litigation settlement paid by Company's insurers	6.7	6.7
Consideration for proposed securities litigation settlement to be paid by Cadence's insurers			22.2
Remaining consideration paid by Cadence's insurers for securities litigation settlement fund subsequent to July 2, 2011	15.5
Plaintiff's attorneys fees to be paid by Cadence's insurers as part of derivative settlement				$ 1.8
Warranty on sale of hardware products to customers		generally for a 90-day period