Revenue Recognition (Details) (USD $) In Millions	3 Months Ended	6 Months Ended
Jul. 02, 2011	Jul. 02, 2011
Revenue Recognition [Abstract]
Change in reported revenue if revenues are accounted under pre existing accounting standards	$ 3.1	$ (2.1)

Name:

cdns_ChangeInReportedRevenueIfRevenuesAreAccountedUnderPreExistingAccountingStandards

Namespace Prefix:

cdns

Data Type:

xbrli:monetaryItemType

Balance Type:

credit

Period Type:

duration