Quarterly Financial Information (Unaudited) (Details) (USD $)	3 Months Ended										12 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		Dec. 29, 2013		Dec. 30, 2012
Quarterly Financial Data [Abstract]
Revenue	$ 608,390,000		$ 542,049,000	$ 556,170,000	$ 530,610,000	$ 591,870,000		$ 522,100,000	$ 540,673,000	$ 502,943,000	$ 2,237,219,000		$ 2,157,586,000
Gross profit	277,602,000		243,309,000	247,984,000	235,713,000	276,770,000		233,268,000	241,662,000	224,442,000	1,004,608,000		976,142,000
Restructuring and contract termination charges, net	(579,000)		11,092,000	742,000	2,135,000	10,211,000		1,124,000	19,247,000	3,310,000	13,390,000		33,892,000		25,051,000
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
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
Operating income from continuing operations	31,314,000	[1]	42,898,000	52,003,000	34,951,000	73,455,000	[2]	40,763,000	27,274,000	32,775,000	161,166,000		174,267,000		71,289,000
Net income	30,787,000	[1]	42,277,000	50,490,000	34,224,000	66,873,000	[2]	40,198,000	27,925,000	32,216,000	157,778,000		167,212,000		69,940,000
Basic earnings per share:
Continuing operations	$ 0.28	[1]	$ 0.38	$ 0.46	$ 0.31	$ 0.65	[2]	$ 0.36	$ 0.24	$ 0.29	$ 1.43		$ 1.55		$ 0.63
Net income	$ 0.27	[1]	$ 0.38	$ 0.45	$ 0.30	$ 0.60	[2]	$ 0.36	$ 0.25	$ 0.28	$ 1.40		$ 1.49		$ 0.61
Diluted earnings per share:
Continuing operations	$ 0.28	[1]	$ 0.38	$ 0.46	$ 0.31	$ 0.65	[2]	$ 0.36	$ 0.24	$ 0.29	$ 1.42		$ 1.54		$ 0.62
Net income	$ 0.27	[1]	$ 0.37	$ 0.44	$ 0.30	$ 0.59	[2]	$ 0.36	$ 0.25	$ 0.28	$ 1.39		$ 1.47		$ 0.61
Cash dividends per common share	$ 0.07		$ 0.07	$ 0.07	$ 0.07	$ 0.07		$ 0.07	$ 0.07	$ 0.07	$ 0.28		$ 0.28
Defined Benefit Plan, Recognized Net Gain (Loss) on Mark-to-Market											75,900,000		(17,600,000)		31,800,000
Tax Adjustments, Settlements, and Unusual Provisions						(9,200,000)					(7,000,000)		(24,000,000)		(7,000,000)
Human Health [Member]
Quarterly Financial Data [Abstract]
Operating income from continuing operations											$ 220,165,000	[3]	$ 156,452,000	[3]	$ 63,773,000	[3]

[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.