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Contingencies (Details) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2018 USD ($) Case | Sep. 30, 2018 USD ($) Case | Oct. 24, 2014 USD ($)
Site Contingency [Abstract] |  |  |
Consent decree paid by US government | $ |  |  | $ 2.3
Silica Cases [Member] |  |  |
Loss Contingency [Abstract] |  |  |
Number of pending cases | 3 | 3 |
Cumulative number of cases dismissed | 1,493 | 1,493 |
Number of cases dismissed | 0 |  |
Number of lawsuits settled |  | 1 |
Asbestos Cases [Member] |  |  |
Loss Contingency [Abstract] |  |  |
Number of pending cases | 29 | 29 |
Cumulative number of cases dismissed | 54 | 54 |
Number of new cases filed during the period | 4 |  |
Number of cases dismissed | 0 |  |
Number of lawsuits settled |  | 0 |
Number of cases claim liability |  | 24 |
Number of allege liability |  | 3 |
Number of cases with no alleged exposure |  | 0 |
Administrative Consent Order for Contamination Associated with Historic Use of PCBs [Member] |  |  |
Site Contingency [Abstract] |  |  |
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 [Abstract] |  |  |
Location of plant |  | Adams, Massachusetts |
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 |

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