Acquisitions and Acquisition-Related Contingent Consideration (Details Textual) (USD $)	12 Months Ended					12 Months Ended				12 Months Ended
	Dec. 29, 2012	Dec. 29, 2012 Denali Software Inc [Member]	Dec. 31, 2011 Denali Software Inc [Member]	Jan. 01, 2011 Denali Software Inc [Member]	Jun. 30, 2010 Denali Software Inc [Member]	Dec. 31, 2011 Other 2010 Acquisition [Member]	Jan. 01, 2011 Other 2010 Acquisition [Member]	Dec. 29, 2012 Sigrity [Member]	Jul. 02, 2012 Sigrity [Member]	Dec. 31, 2011 2011 Acquisitions [Member]
Acquisitions (Textual) [Abstract]
Total consideration paid to acquire business, net of cash acquired					$ 262,800,000.0				$ 78,500,000
Cash acquired					46,700,000				7,500,000
Cash paid for acquired entity at closing					250,200,000				64,300,000	49,300,000
Additional payments deferred on the acquisition date					12,600,000				14,200,000
Additional payments deferred on the acquisition date, expensed		700,000	1,500,000	10,200,000				3,500,000
Additional payments deferred on the acquisition date, expense in future periods		200,000						10,700,000
Decrease in valuation allowance against deferred tax assets	219,600,000			66,700,000				14,800,000
Weighted-average life of definite- lived intangible assets						5 years	5 years			7 years
Goodwill					152,172,000		3,900,000		39,680,000	32,300,000
Business Acquisition Purchase Price Allocation Intangible							2,200,000
Acquired intangibles:							1,700,000			21,600,000
Intangible assets allocated to in - process research and development							500,000
Acquisition-Related Contingent Consideration (Textual) [Abstract]
Maximum payments for contingent consideration arrangement							4,000,000			5,000,000
Time of certain financial measures subsequent to the consummation of the acquisition related to contingent consideration										3 years
Beginning date of acquisition related contingent consideration measurement period										subsequent to October 1, 2011
Acquisition-Related Contingent Consideration (Additional Textual) [Abstract]
Maximum amount obligated to pay by Cadence	18,800,000
Period over which consideration may be paid	40 months
Portion of amount of contingent consideration potential expense in future periods	$ 12,400,000