Subsequent Event Subsequent Event (Details) (2014 Acquisitions [Member], Subsequent Event [Member], USD $) In Millions, unless otherwise specified	Apr. 21, 2014	Dec. 31, 2013
2014 Acquisitions [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Gross cash payable acquire business	$ 170.0
Cash, cash equivalents, and short-term investments held by business to be acquired		$ 24.0

Cash, cash equivalents, and short-term investments held by the business to be acquired as of the most recent fiscal year-end balance sheet date

No definition available.

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