Segment Information (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 782.0	$ 732.5	$ 1,527.2	$ 1,428.1
United States
Disaggregation of Revenue [Line Items]
Net sales	550.5	491.8	1,070.3	963.9
Europe
Disaggregation of Revenue [Line Items]
Net sales	129.2	139.5	250.0	266.5
All other
Disaggregation of Revenue [Line Items]
Net sales	102.3	101.2	206.9	197.7
Fixed Price
Disaggregation of Revenue [Line Items]
Net sales	695.8	658.4	1,358.4	1,280.3
Cost Type
Disaggregation of Revenue [Line Items]
Net sales	86.2	74.1	168.8	147.8
US Government
Disaggregation of Revenue [Line Items]
Net sales	187.0	162.0	356.9	321.5
Other, Primarily Commercial
Disaggregation of Revenue [Line Items]
Net sales	595.0	570.5	1,170.3	1,106.6
Instrumentation
Disaggregation of Revenue [Line Items]
Net sales	264.1	262.6	520.6	501.6
Instrumentation | United States
Disaggregation of Revenue [Line Items]
Net sales	225.1	206.5	436.2	397.5
Instrumentation | Europe
Disaggregation of Revenue [Line Items]
Net sales	30.8	45.4	64.4	84.8
Instrumentation | All other
Disaggregation of Revenue [Line Items]
Net sales	8.2	10.7	20.0	19.3
Instrumentation | Fixed Price
Disaggregation of Revenue [Line Items]
Net sales	253.7	258.5	504.7	492.6
Instrumentation | Cost Type
Disaggregation of Revenue [Line Items]
Net sales	10.4	4.1	15.9	9.0
Instrumentation | US Government
Disaggregation of Revenue [Line Items]
Net sales	18.6	15.8	32.8	28.6
Instrumentation | Other, Primarily Commercial
Disaggregation of Revenue [Line Items]
Net sales	245.5	246.8	487.8	473.0
Digital Imaging
Disaggregation of Revenue [Line Items]
Net sales	251.3	225.3	486.6	436.3
Digital Imaging | United States
Disaggregation of Revenue [Line Items]
Net sales	80.3	59.4	152.7	116.2
Digital Imaging | Europe
Disaggregation of Revenue [Line Items]
Net sales	77.3	76.0	147.6	143.0
Digital Imaging | All other
Disaggregation of Revenue [Line Items]
Net sales	93.7	89.9	186.3	177.1
Digital Imaging | Fixed Price
Disaggregation of Revenue [Line Items]
Net sales	229.8	203.5	443.1	394.7
Digital Imaging | Cost Type
Disaggregation of Revenue [Line Items]
Net sales	21.5	21.8	43.5	41.6
Digital Imaging | US Government
Disaggregation of Revenue [Line Items]
Net sales	26.2	22.5	52.4	44.9
Digital Imaging | Other, Primarily Commercial
Disaggregation of Revenue [Line Items]
Net sales	225.1	202.8	434.2	391.4
Aerospace and Defense Electronics
Disaggregation of Revenue [Line Items]
Net sales	191.0	173.5	371.4	347.1
Aerospace and Defense Electronics | United States
Disaggregation of Revenue [Line Items]
Net sales	171.7	157.0	336.8	311.1
Aerospace and Defense Electronics | Europe
Disaggregation of Revenue [Line Items]
Net sales	18.9	15.9	34.0	34.7
Aerospace and Defense Electronics | All other
Disaggregation of Revenue [Line Items]
Net sales	0.4	0.6	0.6	1.3
Aerospace and Defense Electronics | Fixed Price
Disaggregation of Revenue [Line Items]
Net sales	190.5	173.0	370.6	346.4
Aerospace and Defense Electronics | Cost Type
Disaggregation of Revenue [Line Items]
Net sales	0.5	0.5	0.8	0.7
Aerospace and Defense Electronics | US Government
Disaggregation of Revenue [Line Items]
Net sales	78.5	66.5	146.5	131.8
Aerospace and Defense Electronics | Other, Primarily Commercial
Disaggregation of Revenue [Line Items]
Net sales	112.5	107.0	224.9	215.3
Engineered Systems
Disaggregation of Revenue [Line Items]
Net sales	75.6	71.1	148.6	143.1
Engineered Systems | United States
Disaggregation of Revenue [Line Items]
Net sales	73.4	68.9	144.6	139.1
Engineered Systems | Europe
Disaggregation of Revenue [Line Items]
Net sales	2.2	2.2	4.0	4.0
Engineered Systems | All other
Disaggregation of Revenue [Line Items]
Net sales	0.0	0.0	0.0	0.0
Engineered Systems | Fixed Price
Disaggregation of Revenue [Line Items]
Net sales	21.8	23.4	40.0	46.6
Engineered Systems | Cost Type
Disaggregation of Revenue [Line Items]
Net sales	53.8	47.7	108.6	96.5
Engineered Systems | US Government
Disaggregation of Revenue [Line Items]
Net sales	63.7	57.2	125.2	116.2
Engineered Systems | Other, Primarily Commercial
Disaggregation of Revenue [Line Items]
Net sales	$ 11.9	$ 13.9	$ 23.4	$ 26.9