Debt Credit Facility (Details Textual) (Revolving Credit Facility [Member], USD $)	12 Months Ended
Jan. 03, 2015	Dec. 28, 2013
Line of Credit Facility [Line Items]
Outstanding borrowings under Revolving Credit Facility	$ 0us-gaap_LinesOfCreditCurrent	$ 0us-gaap_LinesOfCreditCurrent
Credit facility date of agreement	Dec. 12, 2012
Credit facility, interest rate description	Interest accrues based on Cadence’s consolidated leverage ratio. Borrowings may be made at LIBOR plus a margin between 1.25% and 2.0% per annum or at the base rate plus a margin between 0.25% and 1.0% per annum, where in each case the margin is determined by reference to a specified leverage ratio. Interest is payable quarterly.
Credit facility, term	5 years
Credit facility, current borrowing capacity	250,000,000
Credit facility, additional borrowing capacity available	150,000,000
Credit cacility, maximum borrowing capacity	$ 400,000,000
Credit facility, maturity date	Sep. 19, 2019
Credit facility, covenant description	The credit facility contains customary negative covenants that, among other things, restrict Cadence’s ability to incur additional indebtedness, grant liens, make certain investments (including acquisitions), dispose of certain assets and make certain restricted payments, including share repurchases and dividends. In addition, the credit facility contains financial covenants that require Cadence to maintain a leverage ratio not to exceed 2.75 to 1, and a minimum interest coverage ratio of 3 to 1.
Credit facility, covenant compliance	Cadence was in compliance with all financial covenants as of January 3, 2015 and December 28, 2013
Maximum [Member]
Line of Credit Facility [Line Items]
Credit facility, commitment fee percentage	0.35%
Minimum [Member]
Line of Credit Facility [Line Items]
Credit facility, commitment fee percentage	0.20%
Credit facility interest LIBOR and spread [Member] \| Maximum [Member]
Line of Credit Facility [Line Items]
Credit facilty, interest rate spread	2.00%
Credit facility interest LIBOR and spread [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Credit facilty, interest rate spread	1.25%
Credit facility interest base rate and spread [Member] \| Maximum [Member]
Line of Credit Facility [Line Items]
Credit facilty, interest rate spread	1.00%
Credit facility interest base rate and spread [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Credit facilty, interest rate spread	0.25%

Line Of Credit Facility, Additional Borrowing Capacity Available

No definition available.

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

- Definition

Term Of Line Of Credit Agreement

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Identification of whether the entity has been in compliance with any credit facility debt covenants during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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

- Definition

Description of the conditions for borrowing under the credit facility including the nature of any restrictions.

+ References

+ Details

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Period Type:	duration

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the credit facility first became available, in CCYY-MM-DD format.

+ References

+ Details

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Data Type:	xbrli:dateItemType
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Period Type:	duration

- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

+ Details

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- Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Line-of-Credit Arrangement

-URI http://asc.fasb.org/extlink&oid=6517033

+ Details

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