Restructuring and Lease Charges, Net (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended			6 Months Ended	3 Months Ended	6 Months Ended					3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		6 Months Ended		3 Months Ended			3 Months Ended						6 Months Ended			3 Months Ended	6 Months Ended	3 Months Ended
	Jul. 01, 2012	Jul. 03, 2011	Jul. 01, 2012	Jul. 03, 2011	Jan. 01, 2012	Jul. 01, 2012 Contract Termination [Member]	Apr. 01, 2012 Q1 2012 Restructuring Plan [Member] employees	Jul. 01, 2012 Q1 2012 Restructuring Plan [Member]	Jul. 01, 2012 Q1 2012 Restructuring Plan [Member] Human Health [Member]	Jul. 01, 2012 Q1 2012 Restructuring Plan [Member] Environmental Health [Member]	Jul. 01, 2012 Q1 2012 Restructuring Plan [Member] Severance [Member]	Jul. 01, 2012 Q1 2012 Restructuring Plan [Member] Closure Of Excess Facility Space [Member]	Jan. 01, 2012 Q4 2011 Restructuring Plan [Member]	Jul. 01, 2012 Q4 2011 Restructuring Plan [Member]	Jan. 01, 2012 Q4 2011 Restructuring Plan [Member] Human Health [Member]	Jan. 01, 2012 Q4 2011 Restructuring Plan [Member] Environmental Health [Member]	Jul. 01, 2012 Q4 2011 Restructuring Plan [Member] Severance [Member]	Jan. 01, 2012 Q4 2011 Restructuring Plan [Member] Severance [Member]	Jul. 01, 2012 Q4 2011 Restructuring Plan [Member] Closure Of Excess Facility Space [Member]	Jan. 01, 2012 Q4 2011 Restructuring Plan [Member] Closure Of Excess Facility Space [Member]	Jul. 03, 2011 Q2 2011 Restructuring Plan [Member] employees	Jul. 01, 2012 Q2 2011 Restructuring Plan [Member]	Jan. 01, 2012 Q2 2011 Restructuring Plan [Member]	Jul. 03, 2011 Q2 2011 Restructuring Plan [Member] Human Health [Member]	Jul. 03, 2011 Q2 2011 Restructuring Plan [Member] Environmental Health [Member]	Jul. 01, 2012 Q2 2011 Restructuring Plan [Member] Severance [Member]	Jan. 01, 2012 Q2 2011 Restructuring Plan [Member] Severance [Member]	Jul. 01, 2012 Q2 2011 Restructuring Plan [Member] Closure Of Excess Facility Space [Member]	Jan. 01, 2012 Q2 2011 Restructuring Plan [Member] Closure Of Excess Facility Space [Member]	Jul. 01, 2012 Previous restructuring and integration plans [Member]	Jul. 01, 2012 Previous restructuring and integration plans [Member] Severance [Member]	Jul. 01, 2012 Previous restructuring and integration plans [Member] Closure Of Excess Facility Space [Member]	Jul. 01, 2012 Q2 2012 Restructuring Plan [Member] employees	Jul. 01, 2012 Q2 2012 Restructuring Plan [Member]	Jul. 01, 2012 Q2 2012 Restructuring Plan [Member] Human Health [Member]	Jul. 01, 2012 Q2 2012 Restructuring Plan [Member] Environmental Health [Member]	Jul. 01, 2012 Q2 2012 Restructuring Plan [Member] Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges before tax	$ 5,203,000	$ 3,340,000	$ 11,362,000	$ 3,340,000					$ 5,400,000	$ 800,000					$ 2,300,000	$ 4,600,000								$ 2,200,000	$ 3,400,000										$ 4,000,000	$ 200,000
Restructuring and Related Cost, Remaining Cost								500,000																										5,400,000
Additional accrual for estimated sublease rental payments and (reversal) related to lower than expected cost associated with workforce reductions														(135,000)			0		(135,000)												400,000	300,000
Number of employees reduced							129						114								72												229
Remaining payments	15,189,000		15,189,000		13,958,000	1,700,000		2,889,000			2,889,000	0	5,044,000	1,616,000			1,441,000	4,674,000	175,000	370,000		829,000	1,283,000			829,000	1,283,000	0	0	12,700,000							3,504,000
Other Restructuring Costs						400,000
Restructuring Reserve, Settled with Cash						800,000
Payments for Restructuring																														$ 2,500,000