Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
Disaggregation of Revenue [Abstract]
Total net sales	$ 437.7	$ 431.3
Metalcasting [Member]
Disaggregation of Revenue [Abstract]
Total net sales	73.2	79.2
Household, Personal Care & Specialty Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	74.9	48.7
Environmental Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	15.9	12.7
Building Materials [Member]
Disaggregation of Revenue [Abstract]
Total net sales	15.3	18.9
Basic Minerals [Member]
Disaggregation of Revenue [Abstract]
Total net sales	19.9	27.8
Paper PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	91.5	97.0
Specialty PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	18.1	17.0
Ground Calcium Carbonate [Member]
Disaggregation of Revenue [Abstract]
Total net sales	22.3	22.5
Talc [Member]
Disaggregation of Revenue [Abstract]
Total net sales	12.5	13.1
Refractory Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	62.0	62.3
Metallurgical Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	11.8	13.0
Performance Materials [Member]
Disaggregation of Revenue [Abstract]
Total net sales	199.2	187.3
Performance Materials [Member] | Metalcasting [Member]
Disaggregation of Revenue [Abstract]
Total net sales	73.2	79.2
Performance Materials [Member] | Household, Personal Care & Specialty Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	74.9	48.7
Performance Materials [Member] | Environmental Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	15.9	12.7
Performance Materials [Member] | Building Materials [Member]
Disaggregation of Revenue [Abstract]
Total net sales	15.3	18.9
Performance Materials [Member] | Basic Minerals [Member]
Disaggregation of Revenue [Abstract]
Total net sales	19.9	27.8
Specialty Minerals [Member]
Disaggregation of Revenue [Abstract]
Total net sales	144.4	149.6
Specialty Minerals [Member] | Paper PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	91.5	97.0
Specialty Minerals [Member] | Specialty PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	18.1	17.0
Specialty Minerals [Member] | Ground Calcium Carbonate [Member]
Disaggregation of Revenue [Abstract]
Total net sales	22.3	22.5
Specialty Minerals [Member] | Talc [Member]
Disaggregation of Revenue [Abstract]
Total net sales	12.5	13.1
Refractories [Member]
Disaggregation of Revenue [Abstract]
Total net sales	73.8	75.3
Refractories [Member] | Refractory Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	62.0	62.3
Refractories [Member] | Metallurgical Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	11.8	13.0
Energy Services [Member]
Disaggregation of Revenue [Abstract]
Total net sales	$ 20.3	$ 19.1