Business Combinations and Asset Purchases (Fair Values of the Business Combinations and Allocations for the Acquisitions Completed) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended	1 Months Ended
	Dec. 28, 2014	Nov. 30, 2012	Dec. 28, 2014	Dec. 29, 2013	Dec. 30, 2012	Oct. 21, 2014	Dec. 05, 2014
Business Acquisition [Line Items]
Goodwill	$ 2,284,077		$ 2,284,077	$ 2,143,120	$ 2,122,788
Fiscal Year 2014 Acquisitions (excluding Perten) [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid	17,898
Working capital and other adjustments	151
Less: cash acquired	124
Total	17,925
Current assets						1,965
Property, plant and equipment						125
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets						364
Goodwill						15,981
Deferred taxes						(3,072)
Business Acquisition, Purchase Price Allocation, Current and Non-current Liabilities, Deferred Revenue						(589)
Liabilities assumed						(2,333)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt						(4,287)
Total						17,925
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
Trade Names [Member] | Fiscal Year 2014 Acquisitions (excluding Perten) [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						0
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
In Process Research and Development [Member] | Fiscal Year 2014 Acquisitions (excluding Perten) [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						1,266
Human Health [Member]
Business Acquisition [Line Items]
Goodwill	1,621,595		1,621,595	1,648,332	1,632,487
Human Health [Member] | Haoyuan Biotech Co. [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid		38,000
Contingent consideration		1,900
Working capital and other adjustments		(2,729)
Less: cash acquired		175
Total		36,996
Current assets		2,389
Property, plant and equipment		2,906
Goodwill		19,682
Deferred taxes		(2,656)
Liabilities assumed		(3,725)
Total		36,996
Human Health [Member] | Core Technology [Member] | Haoyuan Biotech Co. [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		17,700
Human Health [Member] | Trade Names [Member] | Haoyuan Biotech Co. [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		400
Human Health [Member] | In Process Research and Development [Member] | Haoyuan Biotech Co. [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		300
Environmental Health [Member]
Business Acquisition [Line Items]
Goodwill	662,482		662,482	494,788	490,301
Environmental Health [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid			269,937
Working capital and other adjustments			0
Less: cash acquired			16,732
Total			253,205
Current assets							32,805
Property, plant and equipment							1,485
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets							0
Goodwill							164,164
Deferred taxes							(31,454)
Business Acquisition, Purchase Price Allocation, Current and Non-current Liabilities, Deferred Revenue							0
Liabilities assumed							(16,195)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt							(7,600)
Total							253,205
Environmental Health [Member] | Core Technology [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							16,000
Environmental Health [Member] | Trade Names [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							7,000
Environmental Health [Member] | Customer Relationships [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							87,000
Environmental Health [Member] | In Process Research and Development [Member] | Perten Instruments Group AB [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							$ 0