Segment and Related Information, Sales by Product Category (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2016	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue from External Customer [Line Items]
Net sales	$ 432.1	$ 424.5	$ 414.1	$ 405.0	$ 401.3	$ 399.5	$ 427.0	$ 410.2	$ 1,675.7	$ 1,638.0	$ 1,797.6
Paper PCC [Member]
Revenue from External Customer [Line Items]
Net sales									377.7	387.9	423.3
Specialty PCC [Member]
Revenue from External Customer [Line Items]
Net sales									66.0	64.3	64.8
Talc [Member]
Revenue from External Customer [Line Items]
Net sales									53.8	55.7	55.9
Ground Calcium Carbonate [Member]
Revenue from External Customer [Line Items]
Net sales									87.3	83.6	80.6
Metalcasting [Member]
Revenue from External Customer [Line Items]
Net sales									294.3	258.0	266.4
Household, Personal Care & Specialty Products [Member]
Revenue from External Customer [Line Items]
Net sales									169.6	171.2	172.7
Basic Minerals [Member]
Revenue from External Customer [Line Items]
Net sales									125.0	103.9	106.0
Environmental Products [Member]
Revenue from External Customer [Line Items]
Net sales									67.7	78.9	69.8
Building Materials [Member]
Revenue from External Customer [Line Items]
Net sales									78.2	74.1	80.0
Refractory Products [Member]
Revenue from External Customer [Line Items]
Net sales									226.9	219.0	230.7
Metallurgical Products [Member]
Revenue from External Customer [Line Items]
Net sales									52.5	55.5	65.2
Energy Services [Member]
Revenue from External Customer [Line Items]
Net sales									$ 76.7	$ 85.9	$ 182.2