Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Disaggregation of Revenue [Abstract]
Total net sales	$ 449.3	$ 464.1	$ 1,350.8	$ 1,360.1
Performance Materials [Member]
Disaggregation of Revenue [Abstract]
Total net sales	207.3	219.5	621.9	621.3
Performance Materials [Member] | Metalcasting [Member]
Disaggregation of Revenue [Abstract]
Total net sales	69.0	77.8	218.0	245.8
Performance Materials [Member] | Household, Personal Care & Specialty Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	94.1	97.4	280.4	256.4
Performance Materials [Member] | Environmental Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	27.1	26.3	72.0	64.2
Performance Materials [Member] | Building Materials [Member]
Disaggregation of Revenue [Abstract]
Total net sales	17.1	18.0	51.5	54.9
Specialty Minerals [Member]
Disaggregation of Revenue [Abstract]
Total net sales	143.1	146.3	432.6	446.8
Specialty Minerals [Member] | Paper PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	90.2	93.1	271.9	284.6
Specialty Minerals [Member] | Specialty PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	17.7	16.9	53.1	51.2
Specialty Minerals [Member] | Ground Calcium Carbonate [Member]
Disaggregation of Revenue [Abstract]
Total net sales	23.0	23.0	70.1	70.7
Specialty Minerals [Member] | Talc [Member]
Disaggregation of Revenue [Abstract]
Total net sales	12.2	13.3	37.5	40.3
Refractories [Member]
Disaggregation of Revenue [Abstract]
Total net sales	73.4	79.1	224.7	234.0
Refractories [Member] | Refractory Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	61.3	66.7	184.3	195.7
Refractories [Member] | Metallurgical Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	12.1	12.4	40.4	38.3
Energy Services [Member]
Disaggregation of Revenue [Abstract]
Total net sales	$ 25.5	$ 19.2	$ 71.6	$ 58.0