Summary of Significant Accounting Policies - New Accounting Standards (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 29, 2018		Dec. 30, 2017	Dec. 31, 2016	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Income (Loss) Attributable to Parent		$ 345,777		$ 204,101	$ 203,086
Statement of Financial Position [Abstract]
Receivables, net		297,082		190,426
Prepaid expenses and other		92,550		68,266
Long-term receivables		5,972		12,239
Other assets		371,231		230,301
Accounts payable and accrued liabilities		256,526	[1]	221,101
Current portion of deferred revenue		352,456		336,297
Long-term portion of deferred revenue		48,718		61,513
Retained earnings		772,709		341,003		$ 426,932
Accumulated other comprehensive loss		(24,780)		(3,630)
Income Statement [Abstract]
Revenue		2,138,022		1,943,032	1,816,083
Marketing and sales expense		439,669		419,161	395,194
Provision for income taxes		$ 30,613		$ 110,945	$ 34,067
Net income per share - basic		$ 1.26		$ 0.75	$ 0.71
Net income per share - diluted		$ 1.23		$ 0.73	$ 0.70
Net Cash Provided by (Used in) Operating Activities [Abstract]
Deferred income taxes		$ (11,676)		$ 79,934	$ (4,869)
Receivables		87,083		31,032	3,607
Prepaid expenses and other		19,622		25,793	6,903
Other assets		16,077		22,336	6,566
Accounts payable and accrued liabilities		1,553		(25,987)	2,655
Deferred revenue		100,696		33,614	30,742
Accounting Standards Update 2014-09 [Member]
Statement of Financial Position [Abstract]
Retained earnings	[2]					91,640
Accounting Standards Update 2016-01 [Member]
Statement of Financial Position [Abstract]
Retained earnings						2,638
Accounting Standards Update 2016-16 [Member]
Statement of Financial Position [Abstract]
Retained earnings						(8,349)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Income (Loss) Attributable to Parent		5,520
Statement of Financial Position [Abstract]
Receivables, net		(12,099)				47,300
Prepaid expenses and other		(10,055)
Long-term receivables		(623)
Other assets		(17,013)
Accounts payable and accrued liabilities		(17,438)	[1]			23,300
Current portion of deferred revenue		45,119				57,400
Long-term portion of deferred revenue		17,637
Retained earnings		(86,120)				$ 85,400
Accumulated other comprehensive loss		1,012
Income Statement [Abstract]
Marketing and sales expense		3,947
Provision for income taxes		$ (2,364)
Net income per share - basic		$ 0.02
Net income per share - diluted		$ 0.02
Net Cash Provided by (Used in) Operating Activities [Abstract]
Deferred income taxes		$ (2,213)
Receivables		28,226
Prepaid expenses and other		(5,968)
Other assets		(3,461)
Accounts payable and accrued liabilities		10,100
Deferred revenue		5,390
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Income (Loss) Attributable to Parent		351,297
Statement of Financial Position [Abstract]
Receivables, net		284,983
Prepaid expenses and other		82,495
Long-term receivables		5,349
Other assets		354,218
Accounts payable and accrued liabilities		239,088
Current portion of deferred revenue		397,575
Long-term portion of deferred revenue		66,355
Retained earnings		686,589
Accumulated other comprehensive loss		(23,768)
Income Statement [Abstract]
Marketing and sales expense		443,616
Provision for income taxes		$ 28,249
Net income per share - basic		$ 1.28
Net income per share - diluted		$ 1.25
Net Cash Provided by (Used in) Operating Activities [Abstract]
Deferred income taxes		$ (13,889)
Receivables		115,309
Prepaid expenses and other		13,654
Other assets		12,616
Accounts payable and accrued liabilities		11,653
Deferred revenue		106,086
Product and maintenance [Member]
Income Statement [Abstract]
Revenue		1,997,887		1,813,987	1,683,771
Cost of product and maintenance		173,011		156,676	183,291
Product and maintenance [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Income Statement [Abstract]
Revenue		1,031
Cost of product and maintenance		571
Product and maintenance [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Income Statement [Abstract]
Revenue		1,998,918
Cost of product and maintenance		173,582
Technology Service [Member]
Income Statement [Abstract]
Revenue		140,135		129,045	132,312
Cost of product and maintenance		85,736		$ 80,714	$ 73,201
Technology Service [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Income Statement [Abstract]
Revenue		6,643
Technology Service [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Income Statement [Abstract]
Revenue		$ 146,778

[1] Cadence has certain arrangements under which consideration is received from customers prior to identifying the specific goods or services to be delivered under the contract. Cadence records an accrued liability on a contract-by-contract basis at the end of each reporting period for cash consideration received.

[2] The cumulative effect adjustment from the adoption of Revenue from Contracts with Customers (Topic 606) is presented net of the related income tax effect of $17.5 million.