Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 29, 2019		Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Quarterly Financial Data [Abstract]
Revenue	$ 805,496		$ 706,923	$ 722,517	$ 648,737	$ 756,349	$ 674,313	$ 703,362	$ 643,972	$ 2,883,673	$ 2,777,996
Gross profit	398,181		342,275	347,793	307,806	376,250	332,327	340,140	292,222	1,396,055	1,340,939
Restructuring and other costs, net	1,560		14,068	6,161	7,639	(1,942)	6,508	0	6,578	29,428	11,144	$ 12,657
Operating income from continuing operations	138,248	[1]	78,660	91,735	53,330	115,683	80,202	88,064	39,935	361,973	323,884	295,615
Income from continuing operations before income taxes	65,296	[1]	63,254	71,827	36,765	79,429	78,041	71,708	28,505	237,142	257,683	296,718
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(48)		(52)	(54)	(41)	(30)	1,103	(610)	(11)	(195)	452	135,743
Operating income from continuing operations	64,549	[1]	58,610	69,141	35,453	71,322	75,445	64,673	26,035	227,753	237,475	156,890
Net income	$ 64,501	[1]	$ 58,558	$ 69,087	$ 35,412	$ 71,292	$ 76,548	$ 64,063	$ 26,024	$ 227,558	$ 237,927	$ 292,633
Basic earnings per share:
Income from continuing operations	$ 0.58	[1]	$ 0.53	$ 0.62	$ 0.32	$ 0.64	$ 0.68	$ 0.59	$ 0.24	$ 2.06	$ 2.15	$ 1.43
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0.00		0.00	0.00	0.00	0.00	0.01	(0.01)	0.00	0.00	0.00	1.24
Net income	0.58	[1]	0.53	0.62	0.32	0.64	0.69	0.58	0.24	2.06	2.15	2.67
Diluted earnings per share:
Income from continuing operations	0.58	[1]	0.53	0.62	0.32	0.64	0.68	0.58	0.23	2.04	2.13	1.42
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0.00		0.00	0.00	0.00	0.00	0.01	(0.01)	0.00	0.00	0.00	1.22
Net income	0.58	[1]	0.52	0.62	0.32	0.64	0.69	0.57	0.23	2.04	2.13	$ 2.64
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										$ 31,200	$ 21,400
Tax Adjustments, Settlements, and Unusual Provisions										23,400	8,100	$ 98,600
Diagnostics [Member]
Quarterly Financial Data [Abstract]
Operating income from continuing operations										$ 189,330	$ 153,196	$ 146,862

[1] The fourth quarter of fiscal year 2019 includes a pre-tax loss of $31.2 million as a result of the mark-to-market adjustment on postretirement benefit plans. The fourth quarter of fiscal year 2018 includes a pre-tax loss of $21.4 million as a result of the mark-to-market adjustment on postretirement benefit plans. See Note 1 for a discussion of this accounting policy