Segment and Related Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2015 USD ($)	Jun. 29, 2014 USD ($)	Jun. 28, 2015 USD ($) Segment	Jun. 29, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			5
Net Sales	$ 463.4	$ 421.1	$ 916.7	$ 665.5
Income from Operations	52.8	35.8	112.7	59.4
Reportable Segments [Member]
Segment Reporting Information [Line Items]
Income from Operations	57.1	44.9	122.2	75.6
Specialty Minerals [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	156.5	167.9	310.5	327.5
Income from Operations	27.1	23.9	50.2	45.4
Refractories [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	76.4	91.6	150.3	176.4
Income from Operations	8.4	10.1	16.7	19.3
Performance Materials [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	129.1	75.8	257.0	75.8
Income from Operations	25.5	4.3	49.3	4.3
Construction Technologies [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	52.1	37.2	91.0	37.2
Income from Operations	8.3	0.7	12.4	0.7
Energy Services [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	49.3	48.6	107.9	48.6
Income from Operations	$ (12.2)	$ 5.9	$ (6.4)	$ 5.9