Debt (Details Textual) (USD $)			3 Months Ended			3 Months Ended			3 Months Ended	12 Months Ended		1 Months Ended	3 Months Ended
	Mar. 30, 2013	Dec. 29, 2012	Mar. 30, 2013 Convertible Senior Notes Due 2013 [Member]	Dec. 29, 2012 Convertible Senior Notes Due 2013 [Member]	Dec. 30, 2006 Convertible Senior Notes Due 2013 [Member]	Mar. 30, 2013 Convertible Senior Notes Due 2011 [Member]	Dec. 29, 2012 Convertible Senior Notes Due 2011 [Member]	Dec. 30, 2006 Convertible Senior Notes Due 2011 [Member]	Mar. 30, 2013 Convertible Senior Notes Due 2011 [Member] Convertible Senior Notes Due 2013 [Member]	Jan. 01, 2011 Convertible Senior Notes Due 2011 [Member] Convertible Senior Notes Due 2013 [Member]	Dec. 30, 2006 Convertible Senior Notes Due 2011 [Member] Convertible Senior Notes Due 2013 [Member]	Jun. 30, 2010 Convertible Senior Notes Due 2015 [Member]	Mar. 30, 2013 Convertible Senior Notes Due 2015 [Member]	Mar. 31, 2012 Convertible Senior Notes Due 2015 [Member]	Dec. 29, 2012 Convertible Senior Notes Due 2015 [Member]	Mar. 30, 2013 Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]	Dec. 29, 2012 Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]	Aug. 31, 2003 Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]
Convertible Notes (Textual) [Abstract]
Principal amount, issued					$ 250,000,000			$ 250,000,000				$ 350,000,000						$ 420,000,000
Principal amount outstanding			144,461,000	144,461,000		0	0						350,000,000		350,000,000	178,000	178,000
Stated interest rate of Convertible Senior Notes			1.50%			1.375%							2.625%
Net current liability of convertible senior notes	452,571,000	447,011,000											312,729,000
Equity component of convertible debt - included in common stock			63,027,000	63,027,000
Maturity date of Convertible Senior Notes			Dec. 15, 2013			Dec. 15, 2011							Jun. 01, 2015
Warrants to purchase shares of common stock price per share (in usd per share)			$ 31.50						$ 31.50				$ 10.78
Conversion rate of Notes			47.2813 shares of common stock per $1,000 principal amount of notes, which is equivalent to a conversion price of approximately $21.15 per share of Cadence common stock.										132.5205 shares of common stock per $1,000 principal amount of notes, which is equivalent to a conversion price of approximately $7.55 per share of Cadence common stock.
Minimum closing price of common stock for specified days for conversion of notes (in usd per share)			$ 27.50										$ 9.81
Minimum number of trading days limit for which closing price exceeds fixed price for conversion of notes			20 days										20 days
Number of final trading days range within which closing price exceeds the fixed price for conversion of notes			30 days										30 days
Total expense if convertible notes are converted													42,400,000
Unamortized Debt Discount expensed if convertible notes are converted													37,300,000
Unamortized Transaction Fees expensed if convertible notes are converted													5,100,000
If Converted Value of Convertible Senior Notes													646,100,000
Event 1			Closing stock price greater than $27.50 for at least 20 of the last 30 trading days in a calendar quarter (convertible only for subsequent quarter).										Closing stock price greater than $9.81 for at least 20 of the last 30 trading days in a fiscal quarter (convertible only for subsequent quarter).
Event 2			Specified corporate transactions										Specified corporate transactions
Event 3			Note trading price falls below calculated minimum										Note trading price falls below a calculated minimum
Conversion rate of Convertible Senior Notes subject to certain conversion rate adjustments (in usd per share)			$ 21.15										$ 7.55
Condition 1			Upon a fundamental change prior to maturity, the 2013 Note holders could require Cadence to repurchase their notes for cash equal to the principal amount of the notes plus accrued interest. Upon certain fundamental changes, prior to maturity, if Cadence’s stock price were between $18.00 and $60.00 per share at that time, the 2013 Note holder would be entitled to an increase to the conversion rate. This is referred to as a “make-whole premium.”										Upon certain fundamental corporate changes prior to maturity, the 2015 Note holders could require Cadence to repurchase their notes for cash equal to the principal amount of the notes plus accrued interest. Upon certain fundamental changes prior to maturity, if Cadence’s stock price were between $6.16 and $40.00 per share at that time, the 2015 notes holder would be entitled to an increase to the conversion rate. This is referred to as a “make-whole premium.”
Minimum closing price of common stock to make whole premium in the form of increase to conversion rate (in usd per share)			$ 18.00										$ 6.16
Maximum closing price of common stock to make whole premium in form of increase to conversion rate (in usd per share)			$ 60.00										$ 40.00
Conversion rate for convertible senior notes per thousand principal amount of notes			47.2813										132.5205
Debt instrument principal amount conversion rate for specified shares of common stock			1,000										1,000
Total estimated fair value													657,800,000		640,100,000	178,000	178,000
Fair Value of 2015 Notes Embedded Conversion Derivative at the time of issuance												76,600,000
Estimated Fair Value of 2015 Notes Embedded Conversion Derivative at the balance sheet date													315,900,000		303,200,000
Cost of 2015 Notes Hedges												76,600,000
Estimated Fair Value of 2015 Notes hedges at the balance sheet date													315,900,000		303,200,000
Shares of Common Stock that can be purchased under warrants (in shares)											23,600,000		46,400,000
Amount received in cash proceeds from the sale of warrants											39,400,000	37,500,000
Notes Warrants expiration date description			various dates from February 2014 through April 2014			various dates from February 2012 through April 2012							various dates from September 2015 through December 2015
Aggregate cost of 2011 Notes and 2013 Notes Hedges											119,800,000
Portion of 2011 Notes and 2013 Notes hedges sold representing options to purchase Cadence's common stock (in shares)										9,700,000
Proceeds received from sale of 2011 Notes and 2013 Notes Hedges										400,000
Estimated fair value of the remaining 2013 Notes Hedges			300,000	700,000
Number of shares underlying warrants purchased with purchase of 2011 Notes and 2013 Notes (in shares)										9,700,000
Cost for repurchase of portion of 2011 Notes and 2013 Notes Warrants										100,000
Total estimated fair value (including equity component)			145,000,000	144,100,000
Impact on Income statement related to fair value adjustments of 2015 Notes Embedded Conversion Derivative and 2015 Notes Hedges													$ 0	$ 0
Reduction in number of shares available for purchase under warrants (in shares)						7,100,000