Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended					9 Months Ended		12 Months Ended
	Oct. 03, 2021	Dec. 31, 2020	Sep. 27, 2020	Jun. 28, 2020	Mar. 29, 2020	Oct. 03, 2021	Sep. 27, 2020	Dec. 31, 2020
Disaggregation of Revenue [Abstract]
Total net sales	$ 473.2		$ 388.3			$ 1,381.4	$ 1,163.0
Household, Personal Care & Specialty Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	121.8		93.9			333.9	278.0
Metalcasting [Member]
Disaggregation of Revenue [Abstract]
Total net sales	72.9		66.3			235.0	180.8
Environmental Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	39.8		30.2			105.8	104.5
Building Materials [Member]
Disaggregation of Revenue [Abstract]
Total net sales	15.9		13.5			45.0	43.5
Paper PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	89.5		74.5			264.9	225.1
Specialty PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	18.2		17.3			57.1	49.7
Ground Calcium Carbonate [Member]
Disaggregation of Revenue [Abstract]
Total net sales	25.0		23.2			74.5	66.4
Talc [Member]
Disaggregation of Revenue [Abstract]
Total net sales	14.2		10.1			40.9	30.8
Refractory Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	58.3		48.8			175.1	151.7
Metallurgical Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	17.6		10.5			49.2	32.5
Performance Materials [Member]
Disaggregation of Revenue [Abstract]
Total net sales	250.4	$ 219.0	203.9	$ 191.5	$ 211.4	719.7	606.8	$ 825.8
Performance Materials [Member] | Household, Personal Care & Specialty Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	121.8	102.2	93.9	87.9	96.2	333.9	278.0	380.2
Performance Materials [Member] | Metalcasting [Member]
Disaggregation of Revenue [Abstract]
Total net sales	72.9	77.3	66.3	52.8	61.7	235.0	180.8	258.1
Performance Materials [Member] | Environmental Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	39.8	27.1	30.2	37.6	36.7	105.8	104.5	131.6
Performance Materials [Member] | Building Materials [Member]
Disaggregation of Revenue [Abstract]
Total net sales	15.9	$ 12.4	13.5	$ 13.2	$ 16.8	45.0	43.5	$ 55.9
Specialty Minerals [Member]
Disaggregation of Revenue [Abstract]
Total net sales	146.9		125.1			437.4	372.0
Specialty Minerals [Member] | Paper PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	89.5		74.5			264.9	225.1
Specialty Minerals [Member] | Specialty PCC [Member]
Disaggregation of Revenue [Abstract]
Total net sales	18.2		17.3			57.1	49.7
Specialty Minerals [Member] | Ground Calcium Carbonate [Member]
Disaggregation of Revenue [Abstract]
Total net sales	25.0		23.2			74.5	66.4
Specialty Minerals [Member] | Talc [Member]
Disaggregation of Revenue [Abstract]
Total net sales	14.2		10.1			40.9	30.8
Refractories [Member]
Disaggregation of Revenue [Abstract]
Total net sales	75.9		59.3			224.3	184.2
Refractories [Member] | Refractory Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	58.3		48.8			175.1	151.7
Refractories [Member] | Metallurgical Products [Member]
Disaggregation of Revenue [Abstract]
Total net sales	$ 17.6		$ 10.5			$ 49.2	$ 32.5