Segment and Related Information, Sales By Product Category (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 04, 2021	Mar. 29, 2020
Segment and Related Information [Abstract]
Net sales	$ 452.6	$ 417.5
Metalcasting [Member]
Segment and Related Information [Abstract]
Net sales	81.7	61.7
Household, Personal Care & Specialty Products [Member]
Segment and Related Information [Abstract]
Net sales	109.4	96.2
Environmental Products [Member]
Segment and Related Information [Abstract]
Net sales	26.0	36.7
Building Materials [Member]
Segment and Related Information [Abstract]
Net sales	13.8	16.8
Paper PCC [Member]
Segment and Related Information [Abstract]
Net sales	89.6	85.1
Specialty PCC [Member]
Segment and Related Information [Abstract]
Net sales	20.4	17.5
Ground Calcium Carbonate [Member]
Segment and Related Information [Abstract]
Net sales	24.0	22.6
Talc [Member]
Segment and Related Information [Abstract]
Net sales	13.8	11.9
Refractory Products [Member]
Segment and Related Information [Abstract]
Net sales	58.8	55.8
Metallurgical Products [Member]
Segment and Related Information [Abstract]
Net sales	$ 15.1	$ 13.2