Entity Wide Disclosure on Geographic Areas Revenue from External Customers.

Name:	cdns_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAbstract
Namespace Prefix:	cdns
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Entity wide disclosure on geographic areas revenue from external customers attributed to country of domicile and other foreign countries.

+ Details

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

- Definition

Entity Wide Disclosure On Geographic Areas Revenue From External Customers Attributed To Entitys Country Of Domicile Abstract.

+ Details

Name:	cdns_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToEntitysCountryOfDomicileAndOtherForeignCountriesAbstract
Namespace Prefix:	cdns
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Entity wide disclosure on geographic areas revenue from external customers attributed to other foreign countries in region grouped with entity's country of domicile.

+ Details

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

- Definition

Revenues from external customers attributed to the entity's country of domicile.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 131
-Paragraph 38
-Subparagraph a(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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

+ Details

Name:	us-gaap_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToEntitysCountryOfDomicile
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Revenues from external customers attributed to all foreign countries in total from which the entity derives revenues.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 131
-Paragraph 38
-Subparagraph a(2)
-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 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

+ Details

Name:	us-gaap_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToForeignCountries
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 1

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

+ Details

Name:	us-gaap_SalesRevenueNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Segment Reporting (Details) (USD $) In Thousands	3 Months Ended			6 Months Ended
Segment Reporting (Details) (USD $) In Thousands	Jul. 02, 2011	Jul. 03, 2010	Jul. 03, 2010	Jul. 02, 2011	Jul. 03, 2010
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Total revenue	$ 283,270	$ 227,064	$ 227,064	$ 549,372	$ 449,002
Americas:
United States	124,191		94,648	236,210	177,297
Other Americas	8,200		8,352	13,341	13,495
Total Americas	132,391		103,000	249,551	190,792
Total Europe, Middle East and Africa [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries	56,458		52,946	112,734	102,160
Germany [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries	9,319		22,706	21,044	36,882
Other Europe, Middle East and Africa [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries	47,139		30,240	91,690	65,278
Japan [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries	49,194		31,822	99,359	82,875
Asia [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries	$ 45,227		$ 39,296	$ 87,728	$ 73,175