Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Abstract]
Net Sales	$ 440.2	$ 449.3	$ 463.8	$ 437.7	$ 447.5	$ 464.1	$ 464.7	$ 431.3	$ 1,791.0	$ 1,807.6	$ 1,675.7
Metalcasting [Member]
Disaggregation of Revenue [Abstract]
Net Sales									291.2	328.9	294.3
Household, Personal Care and Specialty Products [Member]
Disaggregation of Revenue [Abstract]
Net Sales									376.6	348.5	294.6
Environmental Products [Member]
Disaggregation of Revenue [Abstract]
Net Sales									86.6	80.3	67.7
Building Materials [Member]
Disaggregation of Revenue [Abstract]
Net Sales									68.9	70.4	78.2
Paper PCC [Member]
Disaggregation of Revenue [Abstract]
Net Sales									364.9	378.5	377.7
Specialty PCC [Member]
Disaggregation of Revenue [Abstract]
Net Sales									69.1	66.9	66.0
Ground Calcium Carbonate [Member]
Disaggregation of Revenue [Abstract]
Net Sales									91.3	91.0	87.3
Talc [Member]
Disaggregation of Revenue [Abstract]
Net Sales									49.1	52.9	53.8
Refractory Products [Member]
Disaggregation of Revenue [Abstract]
Net Sales									244.8	261.1	226.9
Metallurgical Products [Member]
Disaggregation of Revenue [Abstract]
Net Sales									53.3	50.8	52.5
Performance Materials [Member]
Disaggregation of Revenue [Abstract]
Net Sales	201.4	207.3	215.4	199.2	206.8	219.5	214.5	187.3	823.3	828.1	734.8
Performance Materials [Member] | Metalcasting [Member]
Disaggregation of Revenue [Abstract]
Net Sales									291.2	328.9	294.3
Performance Materials [Member] | Household, Personal Care and Specialty Products [Member]
Disaggregation of Revenue [Abstract]
Net Sales									376.6	348.5	294.6
Performance Materials [Member] | Environmental Products [Member]
Disaggregation of Revenue [Abstract]
Net Sales									86.6	80.3	67.7
Performance Materials [Member] | Building Materials [Member]
Disaggregation of Revenue [Abstract]
Net Sales									68.9	70.4	78.2
Specialty Minerals [Member]
Disaggregation of Revenue [Abstract]
Net Sales	141.8	143.1	145.1	144.4	142.5	146.3	150.9	149.6	574.4	589.3	584.8
Specialty Minerals [Member] | Paper PCC [Member]
Disaggregation of Revenue [Abstract]
Net Sales									364.9	378.5	377.7
Specialty Minerals [Member] | Specialty PCC [Member]
Disaggregation of Revenue [Abstract]
Net Sales									69.1	66.9	66.0
Specialty Minerals [Member] | Ground Calcium Carbonate [Member]
Disaggregation of Revenue [Abstract]
Net Sales									91.3	91.0	87.3
Specialty Minerals [Member] | Talc [Member]
Disaggregation of Revenue [Abstract]
Net Sales									49.1	52.9	53.8
Refractories [Member]
Disaggregation of Revenue [Abstract]
Net Sales	73.4	73.4	77.5	73.8	77.9	79.1	79.6	75.3	298.1	311.9	279.4
Refractories [Member] | Refractory Products [Member]
Disaggregation of Revenue [Abstract]
Net Sales									244.8	261.1	226.9
Refractories [Member] | Metallurgical Products [Member]
Disaggregation of Revenue [Abstract]
Net Sales									53.3	50.8	52.5
Energy Services [Member]
Disaggregation of Revenue [Abstract]
Net Sales	$ 23.6	$ 25.5	$ 25.8	$ 20.3	$ 20.3	$ 19.2	$ 19.7	$ 19.1	$ 95.2	$ 78.3	$ 76.7