Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jul. 02, 2016	Jul. 04, 2015	Jul. 02, 2016	Jul. 04, 2015
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Total revenue	$ 453,021	$ 415,883	$ 900,883	$ 827,249
Americas:
Total Americas	213,612	199,601	432,875	392,222
United States [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	206,416	192,176	416,438	379,383
Other Americas [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	7,196	7,425	16,437	12,839
Asia [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	111,032	96,426	210,211	195,208
EMEA [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	88,720	82,014	174,184	160,584
Japan [Member]
Entity Wide Disclosure on Geographic Areas Revenue from External Customers
Geographic Areas, revenue from External Customers	$ 39,657	$ 37,842	$ 83,613	$ 79,235

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

No definition available.

+ 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 entity's country of domicile and other foreign countries.

+ References

No definition available.

+ Details

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

- References

No definition available.

+ Details

Name:	us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: 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=26872669&loc=d3e20235-122688

+ Details

Name:	us-gaap_Revenues
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

+ Details

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

- Details

Name:	us-gaap_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=cdns_OtherAmericaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=us-gaap_AsiaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=us-gaap_EMEAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=country_JP
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: