Segment and Related Information, Sales By Product Category (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 02, 2016	Sep. 27, 2015	Oct. 02, 2016	Sep. 27, 2015
Revenue from External Customer [Line Items]
Net Sales	$ 399.5	$ 451.0	$ 1,236.7	$ 1,367.6
Paper PCC [Member]
Revenue from External Customer [Line Items]
Net Sales	95.3	106.1	295.5	315.9
Specialty PCC [Member]
Revenue from External Customer [Line Items]
Net Sales	16.4	15.8	50.2	48.5
Talc [Member]
Revenue from External Customer [Line Items]
Net Sales	13.9	13.9	42.7	41.9
Ground Calcium Carbonate [Member]
Revenue from External Customer [Line Items]
Net Sales	21.7	20.7	65.1	60.6
Refractory Products [Member]
Revenue from External Customer [Line Items]
Net Sales	51.0	60.5	163.3	178.3
Metallurgical Products [Member]
Revenue from External Customer [Line Items]
Net Sales	12.4	16.9	43.2	49.4
Metalcasting [Member]
Revenue from External Customer [Line Items]
Net Sales	63.1	63.4	191.1	200.3
Household, Personal Care and Specialty Products [Member]
Revenue from External Customer [Line Items]
Net Sales	42.1	43.0	131.4	126.6
Basic Minerals and Other Products [Member]
Revenue from External Customer [Line Items]
Net Sales	14.3	20.1	44.6	56.6
Environmental Products [Member]
Revenue from External Customer [Line Items]
Net Sales	24.6	21.7	64.5	55.2
Building Materials and Other Products [Member]
Revenue from External Customer [Line Items]
Net Sales	24.9	28.0	79.5	85.5
Energy Services [Member]
Revenue from External Customer [Line Items]
Net Sales	$ 19.8	$ 40.9	$ 65.6	$ 148.8