Segment and Related Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 03, 2016 USD ($)	Jun. 28, 2015 USD ($)	Jul. 03, 2016 USD ($) Segment	Jun. 28, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			5
Net Sales	$ 427.0	$ 463.4	$ 837.2	$ 916.7
Income from Operations	39.5	52.8	97.1	112.7
Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	427.0	463.4	837.2	916.7
Income from Operations	41.7	57.1	102.3	122.2
Specialty Minerals [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	150.6	156.5	306.2	310.5
Income from Operations	27.6	27.1	53.3	50.2
Refractories [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	73.9	76.4	143.1	150.3
Income from Operations	10.3	8.4	17.1	16.7
Performance Materials [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	128.6	129.1	247.6	257.0
Income from Operations	24.0	25.5	47.8	49.3
Construction Technologies [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	53.9	52.1	94.5	91.0
Income from Operations	9.3	8.3	13.7	12.4
Energy Services [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	20.0	49.3	45.8	107.9
Income from Operations	$ (29.5)	$ (12.2)	$ (29.6)	$ (6.4)