Subsequent Event Subsequent Event (Details) (Subsequent Event [Member], USD $) In Millions, unless otherwise specified	2 Months Ended
Feb. 20, 2014 acquisition
Subsequent Event [Line Items]
Number of acquisitions	2
2014 Acquisitions [Member]
Subsequent Event [Line Items]
Total consideration paid, net of cash acquired	$ 28.0
Estimated cash acquired	$ 2.0

Business acquisition purchase current assets cash and cash equivalents of acquired entity.

No definition available.

Name:	cdns_BusinessAcquisitionPurchaseCurrentAssetsCashAndCashEquivalentsOfAcquiredEntity
Namespace Prefix:	cdns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant