Business Combinations (Narrative) (Details) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Oct. 03, 2021 USD ($) employees	Apr. 04, 2021 USD ($)	Oct. 04, 2020 USD ($)	Oct. 03, 2021 USD ($) employees $ / shares shares	Oct. 04, 2020 USD ($)	Jan. 03, 2021 USD ($) employees $ / shares	Sep. 17, 2021 $ / shares	Jul. 04, 2021 USD ($)	Jul. 05, 2020 USD ($)	Dec. 29, 2019 USD ($)
Business Acquisition [Line Items]
Number of Years in Measurement Period from Acquisition Date to Change Underlying Assumptions				1 year
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value	$ 37,225		$ 2,817	$ 37,225	$ 2,817	$ 2,953		$ 3,334	$ 13,726	$ 35,481
Total transaction costs	(72,500)		(200)	(87,600)	(7,400)
Goodwill	7,420,271			7,420,271		3,447,114
Business Combination, Contingent Consideration, Liability, Current	4,200			4,200		2,900
Business Combination, Contingent Consideration, Liability, Noncurrent	33,000			33,000		100
Foreign Currency Transaction Gain (Loss), before Tax	1,100		1,900	500	(1,600)
Interest Expense	43,531		12,057	74,407	37,308
Business Combination, Contingent Consideration, Liability	37,200			37,200		3,000
Business Combination, Acquisition Related Costs	$ 72,500		200	$ 87,600	7,400
Oxford Immunotec [Member]
Business Acquisition [Line Items]
Entity Number of Employees | employees	275			275
Fiscal Year 2021 Acquisitions (Excluding BioLegend) [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred				$ 958,915
Cash Acquired				195,010
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets	$ 73,933			73,933
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	26,507			26,507
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	15,564			15,564
Cash paid to the shareholders				1,118,884
Business Combination, Consideration Transferred, Liabilities Incurred				$ 910
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				12 years 4 months 24 days
Business Acquisition, Cost of Acquired Entity, Liabilities Incurred, Contingent Consideration at Fair Value				$ 34,131
Goodwill	527,402			527,402
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt	58,594			58,594
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	$ 958,915			958,915
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable				$ 0
Nexcelom Bioscience [Member]
Business Acquisition [Line Items]
Entity Number of Employees | employees	130			130
BioLegend [Member]
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Revenue				$ 3,943		4,025
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual				12,100
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual				6,200
Business Combination, Consideration Transferred				5,688,602
Cash Acquired				292,377
Cash Acquired from Acquisition				(292,400)
Business Acquisition, Cost of Acquired Entity, Consideration Paid in Cash				3,300,000
Business Acquisition, Cost of Acquired Entity, Consideration Paid in Common Stock				2,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets	$ 184,541			184,541
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	147,200			147,200
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	$ 9,330			$ 9,330
Entity Number of Employees | employees	700			700
Cash paid to the shareholders				$ 3,335,753
Business Combination, Consideration Transferred, Liabilities Incurred				$ 6,857
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				16 years 3 months 18 days
Business Acquisition, Cost of Acquired Entity, Liabilities Incurred, Contingent Consideration at Fair Value				$ 0
Goodwill	$ 3,511,498			3,511,498
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt	38,240			38,240
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	5,688,602			5,688,602
Business Acquisition, Pro Forma Income (Loss) from Continuing Operations, Net of Tax				$ 797		$ 552
Business Acquisition, Pro Forma Earnings Per Share, Basic | $ / shares				$ 6,280		$ 4,390
Business Acquisition, Pro Forma Earnings Per Share, Diluted | $ / shares				$ 6,260		$ 4,370
Foreign Currency Transaction Gain (Loss), before Tax				$ (5,400)
Interest Expense				$ 23,600
Business Acquisition, Share Price | $ / shares							$ 187.56
Stock Issued During Period, Shares, Acquisitions | shares				14,066,799
Business Combination, Acquisition Related Costs, Excluded From Proforma Income (Loss) From Continuing Operations				$ 43,200
Business Combination, Bridge Financing and Debt Pre-issuance Hedging Costs, Excluded From Proforma Income (Loss) From Continuing Operations				23,300
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable				2,638,369
Fiscal Year 2020 Acquisitions [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost Of Acquired Entity, Working Capital Adjustments		$ 384
Business Combination, Consideration Transferred		412,097
Cash Acquired		(26,840)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets						$ 35,532
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment						20,302
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets						$ 18,114
Cash paid to the shareholders		437,661
Business Combination, Consideration Transferred, Liabilities Incurred		1,660
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life						11 years
Goodwill						$ 221,960
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt						45,171
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net						$ 412,097
Horizon Discovery Group plc [Member]
Business Acquisition [Line Items]
Entity Number of Employees | employees						400
Shandong Meizheng [Member]
Business Acquisition [Line Items]
Compensation Expense, Excluding Cost of Good and Service Sold	2,100		$ 200	13,800	$ 6,900
Diagnostics [Member]
Business Acquisition [Line Items]
Goodwill	1,979,703			1,979,703		$ 1,691,227
Discovery & Analytical Solutions [Member]
Business Acquisition [Line Items]
Goodwill	5,440,568			5,440,568		1,755,887
Core Technology [Member] | Fiscal Year 2021 Acquisitions (Excluding BioLegend) [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	285,609			285,609
Core Technology [Member] | BioLegend [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	782,400			782,400
Core Technology [Member] | Fiscal Year 2020 Acquisitions [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						65,730
Customer Relationships [Member] | Fiscal Year 2021 Acquisitions (Excluding BioLegend) [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	141,170			141,170
Customer Relationships [Member] | BioLegend [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	1,714,800			1,714,800
Customer Relationships [Member] | Fiscal Year 2020 Acquisitions [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						108,523
Trade Names [Member] | Fiscal Year 2021 Acquisitions (Excluding BioLegend) [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	39,620			39,620
Trade Names [Member] | BioLegend [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 38,000			38,000
Trade Names [Member] | Fiscal Year 2020 Acquisitions [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						5,580
In-process Research and Development [Member] | Fiscal Year 2020 Acquisitions [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						$ 10,700
United States of America, Dollars | Oxford Immunotec [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments				590,900
United States of America, Dollars | Fiscal Year 2021 Acquisitions (Excluding BioLegend) [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments				1,200,000
United States of America, Dollars | Nexcelom Bioscience [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments				267,100
United States of America, Dollars | BioLegend [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments				5,700,000
United States of America, Dollars | Fiscal Year 2021 Other Acquisitions [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments				296,000
United States of America, Dollars | Fiscal Year 2020 Acquisitions [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments		438,900
United States of America, Dollars | Horizon Discovery Group plc [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments		399,800
United States of America, Dollars | Fiscal Year 2020 Other Acquisitions
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments		39,100
United Kingdom, Pounds | Horizon Discovery Group plc [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments		$ 296,000
Cash and Cash Equivalents [Member] | BioLegend [Member]
Business Acquisition [Line Items]
Cash paid to the shareholders				252,600
Senior Unsecured Notes [Member] | BioLegend [Member]
Business Acquisition [Line Items]
Cash paid to the shareholders				2,300,000
Line of Credit, Maturing August 24, 2026 [Member] | BioLegend [Member]
Business Acquisition [Line Items]
Cash paid to the shareholders				310,000
Term Loan Credit Facility Maturing 2024 [Member] | BioLegend [Member]
Business Acquisition [Line Items]
Cash paid to the shareholders				$ 500,000