Convertible Notes (Details) (USD $)	3 Months Ended	6 Months Ended		12 Months Ended	1 Months Ended	3 Months Ended		6 Months Ended			1 Months Ended	6 Months Ended				1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended			1 Months Ended		6 Months Ended
	Jul. 02, 2011	Jul. 02, 2011	Jul. 03, 2010	Jan. 01, 2011	Jun. 30, 2010 Convertible Senior Notes Due 2015 [Member]	Jul. 02, 2011 Convertible Senior Notes Due 2015 [Member]	Jul. 03, 2010 Convertible Senior Notes Due 2015 [Member]	Jul. 02, 2011 Convertible Senior Notes Due 2015 [Member]	Jul. 03, 2010 Convertible Senior Notes Due 2015 [Member]	Jan. 01, 2011 Convertible Senior Notes Due 2015 [Member]	Jun. 30, 2010 Convertible Senior Notes Due 2011 [Member]	Jul. 02, 2011 Convertible Senior Notes Due 2011 [Member]	Jul. 03, 2010 Convertible Senior Notes Due 2011 [Member]	Jan. 01, 2011 Convertible Senior Notes Due 2011 [Member]	Dec. 31, 2006 Convertible Senior Notes Due 2011 [Member]	Dec. 31, 2006 Convertible Senior Notes Due 2011 [Member] Convertible Senior Notes Due 2013 [Member]	Jul. 02, 2011 Convertible Senior Notes Due 2011 [Member] Convertible Senior Notes Due 2013 [Member]	Jul. 03, 2010 Convertible Senior Notes Due 2011 [Member] Convertible Senior Notes Due 2013 [Member]	Jul. 02, 2011 Convertible Senior Notes Due 2011 [Member] Convertible Senior Notes Due 2013 [Member]	Jul. 03, 2010 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]	Jul. 02, 2011 Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]	Aug. 31, 2003 Zero Coupon Zero Yield Senior Convertible Notes Due 2023 [Member]	Nov. 30, 2010 Convertible Senior Notes Due 2013 [Member]	Jun. 30, 2010 Convertible Senior Notes Due 2013 [Member]	Jul. 02, 2011 Convertible Senior Notes Due 2013 [Member]	Jul. 03, 2010 Convertible Senior Notes Due 2013 [Member]	Dec. 31, 2006 Convertible Senior Notes Due 2013 [Member]
Principal amount, Unamortized debt discount and Net carrying amount of the liability component
Principal amount of Convertible Senior Notes					$ 350,000,000	$ 350,000,000		$ 350,000,000		$ 350,000,000							$ 294,461,000		$ 294,461,000		$ 294,461,000
Unamortized debt discount of Convertible Senior Notes						(62,890,000)		(62,890,000)		(69,604,000)							(18,964,000)		(18,964,000)		(25,373,000)
Net liability of Convertible Senior Notes						287,110,000		287,110,000		280,396,000							275,497,000		275,497,000		269,088,000
Effective interest rate, Contractual interest expense and Amortization of debt discount
Effective interest rate						8.10%	8.10%	8.10%	8.10%								6.30%	6.30%	6.30%	6.30%
Contractual interest expense						2,289,000	427,000	4,578,000	427,000								1,053,000	1,649,000	2,106,000	3,440,000
Amortization of debt discount						3,376,000	592,000	6,713,000	592,000								3,212,000	4,706,000	6,409,000	9,801,000
Balance and significant terms of Convertible Notes
Equity component of Convertible Senior Notes																	111,375,000		111,375,000		111,375,000
Principal amount of Convertible Senior Notes					350,000,000	350,000,000		350,000,000		350,000,000							294,461,000		294,461,000		294,461,000
Unamortized debt discount of Convertible Senior Notes						(62,890,000)		(62,890,000)		(69,604,000)							(18,964,000)		(18,964,000)		(25,373,000)
Liability component of Convertible Senior Notes						287,110,000		287,110,000		280,396,000							275,497,000		275,497,000		269,088,000
Effective interest rate, Contractual interest expense and Amortization of debt discount of Senior Notes
Effective interest rate						8.10%	8.10%	8.10%	8.10%								6.30%	6.30%	6.30%	6.30%
Contractual interest expense						2,289,000	427,000	4,578,000	427,000								1,053,000	1,649,000	2,106,000	3,440,000
Amortization of debt discount						3,376,000	592,000	6,713,000	592,000								3,212,000	4,706,000	6,409,000	9,801,000
Convertible Notes (Textuals)
Stated interest rate of Convertible Senior Notes					2.625%							1.375%														1.50%
Maturity date of Convertible Senior Notes								Jun. 01, 2015				Dec. 15, 2011														Dec. 15, 2013
Transaction fees and expenses capitalized as deferred financing costs of Cash Convertible Senior Notes issued Due 2015							10,600,000		10,600,000
Interest rate payable term for Convertible Senior Notes								semi-annually each December 1st and June 1st											semi-annually each December 15th and June 15th
Net proceeds used to purchase Convertible Senior Notes									187,200,000
Proceeds used for repurchase of common stock	0		39,997,000
Event 1						Closing sale price of Cadence's common stock exceeds $9.81 for 20 or more trading days in a period of 30 consecutive trading days ending on the last trading day of the immediately preceding quarter													The price of Cadence’s common stock exceeds $27.50 during certain periods of time specified in the Convertible Senior Notes
Event 2						Specified corporate transactions occur;													Specified corporate transactions occur
Event 3						The trading price of the 2015 Notes falls below 98% of the product of (i) the closing sale price of Cadence’s common stock and (ii) the conversion rate on that date													The trading price of the Convertible Senior Notes falls below 98% of the product of (i) the closing sale price of Cadence’s common stock and (ii) the conversion rate on that date
Number of days during which reported sale price of common stock exceeded $9.81 during last 30 consecutive trading days						more than 20
Conversion rate of Notes								132.5205 shares of Cadence common stock per $1,000 principal amount of 2015 Notes.											47.2813 shares of Cadence common stock per $1,000 principal amount of Convertible Senior Notes
Conversion price of Convertible Senior Notes subject to certain conversion rate adjustments						$ 7.55		$ 7.55									$ 21.15		$ 21.15
Condition 1						If a fundamental change occurs prior to maturity and Cadence's stock price is greater than $6.16 per share at that time, the cash conversion rate will increase by an additional amount of up to 29.8171 shares of Cadence’s common stock per $1,000 principal amount of 2015 Notes which amount would be paid entirely in cash to each holder that elects to convert its 2015 Notes at that time													If a fundamental change occurs prior to maturity and Cadence’s stock price is greater than $18.00 per share at that time, the conversion rate will increase by an additional amount of up to $8.27 per share, which amount would be paid entirely in cash to each holder that elects to convert its Convertible Senior Notes at that time
Condition 2						A fundamental change is any transaction or event (whether by means of an exchange offer, liquidation, tender offer, consolidation, merger, combination, reclassification, recapitalization or otherwise) in which more than 50% of Cadence’s common stock is exchanged for, converted into, acquired for or constitutes solely the right to receive, consideration													A fundamental change is any transaction or event (whether by means of an exchange offer, liquidation, tender offer, consolidation, merger, combination, reclassification, recapitalization or otherwise) in which more than 50% of Cadence’s common stock is exchanged for, converted into, acquired for or constitutes solely the right to receive, consideration
Condition 3						No fundamental change will have occurred if at least 90% of the consideration received consists of shares of common stock, or depositary receipts representing such shares													No fundamental change will have occurred if at least 90% of the consideration received consists of shares of common stock, or depositary receipts representing such shares
Fair Value of 2015 Notes Embedded Conversion Derivative at the time of issuance					76,600,000
Fair Value of 2015 Notes Embedded Conversion Derivative at the Balance Sheet date						222,100,000		222,100,000
Cost of 2015 Notes Hedges					76,600,000
Fair Value of 2015 Notes hedges at the balance sheet date						222,100,000		222,100,000
Impact on Income statement related to adjustments to fair value		0
Shares of Common Stock that can be purchased under warrants								46,400,000											23,600,000
Warrants to purchase shares of common stock price per share in private placement						$ 10.78						$ 31.50														$ 31.50
Principal amount, issued															250,000,000								420,000,000					250,000,000
Remaining principal amount outstanding												150,000,000										200,000				144,500,000
Principal amount repurchased				(205,539,000)							100,000,000		100,000,000											5,500,000	100,000,000		100,000,000
Total fair value of notes						537,000,000		537,000,000														200,000
Current liability for notes						287,100,000		287,100,000				146,700,000		143,300,000
Principal amount of Convertible Senior Notes					350,000,000	350,000,000		350,000,000		350,000,000							294,461,000		294,461,000		294,461,000
Maximum purchase of Cadence's common stock shares, price per share																			$ 31.50
Aggregate cost of Convertible Senior Notes Hedges																119,800,000
Portion of sold of convertible senior notes hedges representing options to purchase Cadence's common stock																					9,700,000
Proceeds received from sale of Convertible Senior Notes Hedges																					400,000
Estimated fair value of the remaining Convertible Senior Notes Hedges																	2,400,000		2,400,000
Amount received in cash proceeds from the sale of the Convertible Senior Notes Warrants																39,400,000
Number of shares underlying warrants purchased with purchase of Convertible Senior Notes																					9,700,000
Cost for repurchase of portion of Convertible Senior Notes Warrants																					100,000
Total fair value (including equity component)																	289,400,000		289,400,000
Proceeds from Convertible Debt			350,000,000		350,000,000
Additional Convertible Notes (Textuals)
Shares repurchased	0		6,493,000
Amount received in cash proceeds from the sale of the 2015 Warrants			$ 37,450,000