Segment and Related Information, Reportable Segments (Details) $ in Millions	3 Months Ended
	Mar. 29, 2020 USD ($) Segment	Mar. 31, 2019 USD ($)
Segment Reporting Information [Abstract]
Number of reportable segments | Segment	4
Net sales	$ 417.5	$ 437.7
Income from operations	57.7	62.0
Performance Materials [Member]
Segment Reporting Information [Abstract]
Net sales	186.2	199.2
Specialty Minerals [Member]
Segment Reporting Information [Abstract]
Net sales	137.1	144.4
Refractories [Member]
Segment Reporting Information [Abstract]
Net sales	69.0	73.8
Energy Services [Member]
Segment Reporting Information [Abstract]
Net sales	25.2	20.3
Reportable Segments [Member]
Segment Reporting Information [Abstract]
Net sales	417.5	437.7
Income from operations	58.8	62.8
Reportable Segments [Member] | Performance Materials [Member]
Segment Reporting Information [Abstract]
Net sales	186.2	199.2
Income from operations	24.1	26.3
Reportable Segments [Member] | Specialty Minerals [Member]
Segment Reporting Information [Abstract]
Net sales	137.1	144.4
Income from operations	20.3	22.0
Reportable Segments [Member] | Refractories [Member]
Segment Reporting Information [Abstract]
Net sales	69.0	73.8
Income from operations	11.2	12.1
Reportable Segments [Member] | Energy Services [Member]
Segment Reporting Information [Abstract]
Net sales	25.2	20.3
Income from operations	$ 3.2	$ 2.4