Contingencies (Details Textual)	9 Months Ended
Sep. 29, 2018
Contingencies (Textual) [Abstract]
General period of warranty on sales of hardware products	90 days

General period of warranty on sales of hardware products.

No definition available.

Name:	cdns_GeneralPeriodOfWarrantyOnSalesOfHardwareProducts
Namespace Prefix:	cdns_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration