Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 01, 2018	Apr. 02, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 431.3	$ 405.0
Metalcasting [Member]
Disaggregation of Revenue [Line Items]
Net sales	79.2	66.6
Household, Personal Care & Specialty Products [Member]
Disaggregation of Revenue [Line Items]
Net sales	48.7	41.1
Environmental Products [Member]
Disaggregation of Revenue [Line Items]
Net sales	12.7	10.6
Building Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales	18.9	17.4
Basic Minerals [Member]
Disaggregation of Revenue [Line Items]
Net sales	27.8	34.2
Paper PCC [Member]
Disaggregation of Revenue [Line Items]
Net sales	97.0	93.4
Specialty PCC [Member]
Disaggregation of Revenue [Line Items]
Net sales	17.0	17.0
Talc [Member]
Disaggregation of Revenue [Line Items]
Net sales	13.1	14.3
Ground Calcium Carbonate [Member]
Disaggregation of Revenue [Line Items]
Net sales	22.5	21.5
Refractory Products [Member]
Disaggregation of Revenue [Line Items]
Net sales	62.3	56.7
Metallurgical Products [Member]
Disaggregation of Revenue [Line Items]
Net sales	13.0	13.5
Performance Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales	187.3	169.9
Performance Materials [Member] | Metalcasting [Member]
Disaggregation of Revenue [Line Items]
Net sales	79.2	66.6
Performance Materials [Member] | Household, Personal Care & Specialty Products [Member]
Disaggregation of Revenue [Line Items]
Net sales	48.7	41.1
Performance Materials [Member] | Environmental Products [Member]
Disaggregation of Revenue [Line Items]
Net sales	12.7	10.6
Performance Materials [Member] | Building Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales	18.9	17.4
Performance Materials [Member] | Basic Minerals [Member]
Disaggregation of Revenue [Line Items]
Net sales	27.8	34.2
Specialty Minerals [Member]
Disaggregation of Revenue [Line Items]
Net sales	149.6	146.2
Specialty Minerals [Member] | Paper PCC [Member]
Disaggregation of Revenue [Line Items]
Net sales	97.0	93.4
Specialty Minerals [Member] | Specialty PCC [Member]
Disaggregation of Revenue [Line Items]
Net sales	17.0	17.0
Specialty Minerals [Member] | Talc [Member]
Disaggregation of Revenue [Line Items]
Net sales	13.1	14.3
Specialty Minerals [Member] | Ground Calcium Carbonate [Member]
Disaggregation of Revenue [Line Items]
Net sales	22.5	21.5
Refractories [Member]
Disaggregation of Revenue [Line Items]
Net sales	75.3	70.2
Refractories [Member] | Refractory Products [Member]
Disaggregation of Revenue [Line Items]
Net sales	62.3	56.7
Refractories [Member] | Metallurgical Products [Member]
Disaggregation of Revenue [Line Items]
Net sales	13.0	13.5
Energy Services [Member]
Disaggregation of Revenue [Line Items]
Net sales	$ 19.1	$ 18.7