Segment and Related Information, Sales By Product Category (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 03, 2016	Mar. 29, 2015
Revenue from External Customer [Line Items]
Net Sales	$ 410.2	$ 453.3
Paper PCC [Member]
Revenue from External Customer [Line Items]
Net Sales	103.2	105.2
Specialty PCC [Member]
Revenue from External Customer [Line Items]
Net Sales	16.7	16.5
Talc [Member]
Revenue from External Customer [Line Items]
Net Sales	15.0	13.8
Ground Calcium Carbonate [Member]
Revenue from External Customer [Line Items]
Net Sales	20.7	18.5
Refractory Products [Member]
Revenue from External Customer [Line Items]
Net Sales	53.4	58.3
Metallurgical Products [Member]
Revenue from External Customer [Line Items]
Net Sales	15.8	15.6
Metalcasting [Member]
Revenue from External Customer [Line Items]
Net Sales	60.0	65.2
Household, Personal Care and Specialty Products [Member]
Revenue from External Customer [Line Items]
Net Sales	45.3	41.8
Basic Minerals and Other Products [Member]
Revenue from External Customer [Line Items]
Net Sales	13.7	20.9
Environmental Products [Member]
Revenue from External Customer [Line Items]
Net Sales	13.4	11.4
Building Materials and Other Products [Member]
Revenue from External Customer [Line Items]
Net Sales	27.2	27.5
Energy Services [Member]
Revenue from External Customer [Line Items]
Net Sales	$ 25.8	$ 58.6