Schedule of Sales and Operating Income from Continuing Operations by Operating Segment (Details) (USD $)	3 Months Ended										12 Months Ended						3 Months Ended
	Dec. 28, 2014		Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 29, 2013		Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 28, 2014 segments		Dec. 29, 2013		Dec. 30, 2012		Dec. 30, 2012
Schedule of Segment Reporting Information, by Segment [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)											$ 0
Asset impairment											0		158,000		74,153,000
Number of Operating Segments											2
Sales Revenue, Goods, Net											1,540,075,000		1,498,070,000		1,474,674,000
Service revenue											697,144,000		659,516,000		630,514,000
Total revenue											2,237,219,000		2,157,586,000		2,105,188,000
Operating income from continuing operations	30,567,000	[1]	58,776,000	69,637,000	51,762,000	92,930,000	[2]	57,954,000	40,216,000	36,694,000	210,742,000		227,794,000		103,120,000
Interest and other expense (income), net											41,139,000		64,110,000		47,956,000
Income from continuing operations before income taxes	20,647,000	[1]	47,810,000	60,673,000	40,473,000	66,065,000	[2]	45,614,000	27,351,000	24,654,000	169,603,000		163,684,000		55,164,000
Defined Benefit Plan, Recognized Net Gain (Loss) on Mark-to-Market											75,900,000		(17,600,000)		31,800,000
Payments for Legal Settlements											7,000,000
Loss Contingency Accrual						3,700,000							3,700,000
Enzo Biochem, Inc. Complaint [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Loss Contingency Accrual, Period Increase (Decrease)											3,300,000
Litigation Settlement, Expense											3,400,000
Human Health [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Sales Revenue, Goods, Net											996,767,000		957,022,000		926,733,000
Service revenue											246,635,000		244,088,000		237,892,000
Total revenue											1,243,402,000		1,201,110,000		1,164,625,000
Operating income from continuing operations											220,165,000	[3]	156,452,000	[3]	63,773,000	[3]
Environmental Health [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Sales Revenue, Goods, Net											543,308,000		541,048,000		547,941,000
Service revenue											450,509,000		415,428,000		392,622,000
Total revenue											993,817,000		956,476,000		940,563,000
Operating income from continuing operations											109,129,000	[3]	97,052,000	[3]	111,844,000	[3]
Corporate [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Operating income from continuing operations											(118,552,000)	[4],[5]	(25,710,000)	[4],[5]	(72,497,000)	[4],[5]
Customer Lists [Member] | Human Health [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)													200,000
Asset impairment						200,000
Trade Names And Trademarks [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)																	74,200,000
Asset impairment															71,900,000
Asset impairment															2,300,000
Trade Names And Trademarks [Member] | Human Health [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)																	73,400,000
Trade Names And Trademarks [Member] | Environmental Health [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)																	$ 700,000

[1] The fourth quarter of fiscal year 2014 includes a pre-tax loss of $75.9 million as a result of the mark-to-market adjustment on postretirement benefit plans. See Note 1 for a discussion of this accounting policy.

[2] The fourth quarter of fiscal year 2013 includes pre-tax income of $17.6 million as a result of the mark-to-market adjustment on postretirement benefit plans. The fourth quarter of fiscal year 2013 also includes a tax benefit of $9.2 million related to discrete items primarily for lapses in statutes of limitations and audit settlements.

[3] Pre-tax impairment charges have been included in the Human Health and Environmental Health operating income from continuing operations. The Company had no pre-tax impairment charges in fiscal year 2014. The Company recognized a $0.2 million pre-tax impairment charge in the Human Health segment in fiscal year 2013. The Company recognized $73.4 million of pre-tax impairment charges in the Human Health segment and also recognized $0.7 million of pre-tax impairment charges in the Environmental Health segment in fiscal year 2012.

[4] Includes expenses related to litigation with Enzo Biochem, Inc. and Enzo Life Sciences, Inc. (collectively, “Enzo”). Enzo filed a complaint in 2002 alleging that the Company separately and together with other defendants breached distributorship and settlement agreements with Enzo, infringed Enzo's patents, engaged in unfair competition and fraud, and committed torts against Enzo by, among other things, engaging in commercial development and exploitation of Enzo's patented products and technology. The Company entered into a settlement agreement with Enzo dated June 20, 2014 and during fiscal year 2014 paid $7.0 million into a designated escrow account to resolve this matter, of which $3.7 million had been accrued in previous years and $3.3 million was recorded during fiscal year 2014. In addition, $3.4 million of expenses were incurred and recorded in preparation for the trial during fiscal year 2014.

[5] Activity related to the mark-to-market adjustment on postretirement benefit plans has been included in the Corporate operating loss from continuing operations, and in the aggregate constituted a pre-tax loss of $75.9 million in fiscal year 2014, pre-tax income of $17.6 million in fiscal year 2013, and a pre-tax loss of $31.8 million in fiscal year 2012.