Contingencies (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 28, 2015 USD ($) Cases	Jun. 28, 2015 USD ($) Contract Load Cases	Oct. 24, 2014 USD ($)	Dec. 31, 2009
Loss Contingencies [Line Items]
Number of contracts entered | Contract		2
Number of ship loads | Load		60
Default arbitration award | $		$ 70.0
Site Contingency [Line Items]
Consent decree paid by US government | $			$ 2.3
AMCOL International Corporation [Member]
Loss Contingencies [Line Items]
Ownership interest (in hundredths)	19.00%	19.00%		20.00%
Administrative Consent Order For Contamination Associated with Historic Use of PCBs [Member]
Site Contingency [Line Items]
Location of plant		Canaan, Connecticut
Estimated accrued remediation cost | $	$ 0.4	$ 0.4
Administrative Consent Order For Installation of Groundwater Contamination System [Member]
Site Contingency [Line Items]
Location of plant		Adams, Massachusetts plant
Estimated accrued remediation cost | $	$ 0.4	$ 0.4
Estimated cost of wastewater treatment upgrades, lower range | $		6.0
Estimated cost of wastewater treatment upgrades, upper range | $		$ 8.0
Silica Cases [Member]
Loss Contingencies [Line Items]
Number of pending cases	74	74
Number of cases dismissed to date	3	1,422
Number of new cases filed during the quarter	0
Number of cases settle		1
Asbestos Cases [Member]
Loss Contingencies [Line Items]
Number of pending cases	13	13
Number of cases dismissed to date	2	44
Number of new cases filed during the quarter	2
Number of cases settle		0
Number of allege liability		1