Litigation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) Contract Load Case	Oct. 24, 2014 USD ($)	Dec. 31, 2009
Loss Contingencies [Line Items]
Number of contracts entered | Contract	2
Number of ship loads | Load	60
Default arbitration awards | $	$ 70.0
Number of cases dismissed	0
Site Contingency [Line Items]
Consent decree paid by US government | $		$ 2.3
AMCOL International Corporation [Member]
Loss Contingencies [Line Items]
Ownership interest	19.00%		20.00%
Silica Cases [Member]
Loss Contingencies [Line Items]
Number of pending cases	3
Cumulative number of cases dismissed	1,493
Number of lawsuits settled	1
Asbestos Cases [Member]
Loss Contingencies [Line Items]
Number of pending cases	20
Cumulative number of cases dismissed	53
Number of new cases filed	7
Number of previously reported cases	1
Number of cases dismissed	4
Number of lawsuits settled	0
Number of cases claim liability	13
Number of allege liability	6
Number of cases with no alleged exposure	0
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
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
Estimated cost of wastewater treatment upgrades, lower range | $	6.0
Estimated cost of wastewater treatment upgrades, upper range | $	$ 8.0