The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
Intangibles (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 794,318		$ 794,318		$ 779,822
Finite-Lived Intangible Assets, Accumulated Amortization	(385,737)		(385,737)		$ (333,507)
Amortization of Intangible Assets	16,900	$ 17,300	51,400	$ 48,100
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	64,119		64,119
Finite-Lived Intangible Assets, Amortization Expense, Year Two	60,564		60,564
Finite-Lived Intangible Assets, Amortization Expense, Year Three	54,096		54,096
Finite-Lived Intangible Assets, Amortization Expense, Year Four	45,053		45,053
Finite-Lived Intangible Assets, Amortization Expense, Year Five	35,892		35,892
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	148,857		148,857
Finite-Lived Intangible Assets, Net	408,581		$ 408,581
Customer Lists
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			8 years 8 months 12 days		9 years 2 months 12 days
Finite-Lived Intangible Assets, Gross	726,631		$ 726,631		$ 717,397
Finite-Lived Intangible Assets, Accumulated Amortization	(331,670)		$ (331,670)		$ (283,846)
Backlog
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			6 months		1 year 3 months 18 days
Finite-Lived Intangible Assets, Gross	31,336		$ 31,336		$ 29,426
Finite-Lived Intangible Assets, Accumulated Amortization	(30,389)		$ (30,389)		$ (28,283)
Developed Technology Rights
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			7 years 3 months 18 days		5 years 2 months 12 days
Finite-Lived Intangible Assets, Gross	36,351		$ 36,351		$ 32,999
Finite-Lived Intangible Assets, Accumulated Amortization	(23,678)		(23,678)		(21,378)
Tradenames And Trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived Intangible Assets (Excluding Goodwill)	$ 1,012,019		$ 1,012,019		$ 997,066