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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 |  |

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