Business Combinations (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Dec. 28, 2014	Jan. 03, 2016	Oct. 04, 2015	Sep. 28, 2014	Oct. 04, 2015	Sep. 28, 2014	Dec. 28, 2014	Jun. 28, 2015	Dec. 05, 2014	Oct. 21, 2014	Jun. 29, 2014	Dec. 29, 2013
Business Acquisition [Line Items]
Number of Years in Measurement Period from Acquisition Date to Change Underlying Assumptions					1 year
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High			$ 2,400		$ 2,400
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	$ 91		519	$ 1,286	$ 519	$ 1,286	$ 91	$ 475			$ 3,430	$ 4,926
Business Combination, Contingent Consideration Arrangements, Maximum Period					3 years
Total transaction costs			100	$ 40	$ 500	$ 200
Business Combination, Contingent Consideration Arrangements, Description					Contingent consideration is measured at fair value at the acquisition date, based on the probability that revenue thresholds or product development milestones will be achieved during the earnout period, with changes in the fair value after the acquisition date affecting earnings to the extent it is to be settled in cash.
Goodwill	2,284,077		2,253,943		$ 2,253,943		2,284,077
Fiscal Year 2015 Acquisitions [Member]
Business Acquisition [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Deferred Taxes			500
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments					19,000
Goodwill			13,200		13,200
Intangible Assets, Gross (Excluding Goodwill)			6,100		6,100
Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles			2,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities			(1,200)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Deferred Taxes			(200)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other Current Assets			(200)
Goodwill, Purchase Accounting Adjustments			(400)
Goodwill, Other Changes					21,400		8,200
Business Acquisition, Goodwill, Expected Tax Deductible Amount									$ 0
Fiscal Year 2014 Acquisitions (excluding Perten) [Member]
Business Acquisition [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred			500
Business Acquisition, Cost of Acquired Entity, Cash Paid Including Working Capital And Other Adjustments							17,600
Business Acquisition, Goodwill, Expected Tax Deductible Amount										$ 0
Cash paid to the shareholders							17,898
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt										(4,287)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities										2,285
Goodwill										15,518
Environmental Health [Member]
Business Acquisition [Line Items]
Goodwill	621,322		610,173		610,173		621,322
Environmental Health [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Cash paid to the shareholders	$ 269,937
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt									(7,600)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities									17,422
Goodwill									163,816
Environmental Health [Member] | Minimum [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years
Environmental Health [Member] | Maximum [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Human Health [Member]
Business Acquisition [Line Items]
Goodwill	$ 1,662,755		$ 1,643,770		$ 1,643,770		$ 1,662,755
Core Technology [Member] | Fiscal Year 2014 Acquisitions (excluding Perten) [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles										1,705
Core Technology [Member] | Environmental Health [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles									17,000
Customer Relationships [Member] | Fiscal Year 2014 Acquisitions (excluding Perten) [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles										$ 6,800
Customer Relationships [Member] | Environmental Health [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles									$ 87,000
Subsequent Event [Member] | Fiscal Year 2015 Acquisitions [Member]
Business Acquisition [Line Items]
Cash paid to the shareholders		$ 23,000