Segment and Related Information (Details) $ in Millions	3 Months Ended
	Apr. 01, 2018 USD ($) Segment	Apr. 02, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	4
Net Sales	$ 431.3	$ 405.0
Income from Operations	62.6	62.1
Performance Materials [Member]
Segment Reporting Information [Line Items]
Net Sales	187.3	169.9
Specialty Minerals [Member]
Segment Reporting Information [Line Items]
Net Sales	149.6	146.2
Refractories [Member]
Segment Reporting Information [Line Items]
Net Sales	75.3	70.2
Energy Services [Member]
Segment Reporting Information [Line Items]
Net Sales	19.1	18.7
Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	431.3	405.0
Income from Operations	64.6	64.1
Reportable Segments [Member] | Performance Materials [Member]
Segment Reporting Information [Line Items]
Net Sales	187.3	169.9
Income from Operations	26.2	28.8
Reportable Segments [Member] | Specialty Minerals [Member]
Segment Reporting Information [Line Items]
Net Sales	149.6	146.2
Income from Operations	24.1	24.4
Reportable Segments [Member] | Refractories [Member]
Segment Reporting Information [Line Items]
Net Sales	75.3	70.2
Income from Operations	12.8	9.2
Reportable Segments [Member] | Energy Services [Member]
Segment Reporting Information [Line Items]
Net Sales	19.1	18.7
Income from Operations	$ 1.5	$ 1.7