Debt (Details Textual) (USD $)	12 Months Ended							12 Months Ended				12 Months Ended			1 Months Ended	12 Months Ended						12 Months Ended
	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011	Dec. 29, 2012 Convertible Senior Notes Due 2013 [Member]	Jan. 01, 2011 Convertible Senior Notes Due 2013 [Member]	Dec. 31, 2011 Convertible Senior Notes Due 2013 [Member]	Dec. 30, 2006 Convertible Senior Notes Due 2013 [Member]	Jan. 01, 2011 Convertible Notes Due Twenty-Eleven [Member]	Dec. 29, 2012 Convertible Senior Notes Due 2011 [Member]	Dec. 31, 2011 Convertible Senior Notes Due 2011 [Member]	Dec. 30, 2006 Convertible Senior Notes Due 2011 [Member]	Dec. 29, 2012 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]	Dec. 29, 2012 Convertible Senior Notes Due 2015 [Member]	Dec. 31, 2011 Convertible Senior Notes Due 2015 [Member]	Jan. 01, 2011 Convertible Senior Notes Due 2015 [Member]	Dec. 29, 2012 Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]	Dec. 31, 2011 Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]	Aug. 31, 2003 Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]	Jan. 01, 2011 First Repurchase [Member] Convertible Senior Notes Due 2013 [Member]	Jan. 01, 2011 Second Repurchase [Member] Convertible Senior Notes Due 2013 [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	447,011,000	294,061,000														308,819,000
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																46,900,000
Unamortized Debt Discount expensed if convertible notes are converted																41,200,000
Unamortized Transaction Fees expensed if convertible notes are converted																5,700,000
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 holders of the notes 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 holders of the notes 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
If-converted value of Convertible Senior Notes																623,400,000
Total estimated fair value																640,100,000	527,800,000		200,000	200,000
Total estimated fair value (including equity component)				144,100,000		142,300,000
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																303,200,000	215,100,000
Cost of 2015 Notes Hedges															76,600,000
Estimated Fair Value of 2015 Notes hedges at the balance sheet date																303,200,000	215,100,000
Impact on Income statement related to fair value adjustments of 2015 Notes Embedded Conversion Derivative and 2015 Notes Hedges																0	0	0
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	0	0	37,450,000											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
Debt Instrument, Decrease, Repayments			205,539,000		105,539,000			100,000,000														100,000,000	5,500,000
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				700,000		1,400,000
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
Reduction in number of shares available for purchase under warrants (in shares)									7,100,000