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Goodwill and Other Intangible Assets, Goodwill (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Goodwill [Roll Forward] |  |
Balance Beginning | $ 807.4 | $ 812.4
Change in goodwill relating to [Abstract] |  |
Foreign exchange translation | 1.1 | (5.0)
Total changes | 1.1 | (5.0)
Balance Ending | 808.5 | 807.4
Performance Materials [Member] |  |
Goodwill [Roll Forward] |  |
Balance Beginning | 751.2 | 755.9
Change in goodwill relating to [Abstract] |  |
Foreign exchange translation | 1.2 | (4.7)
Total changes | 1.2 | (4.7)
Balance Ending | 752.4 | 751.2
Specialty Minerals [Member] |  |
Goodwill [Roll Forward] |  |
Balance Beginning | 12.5 | 12.3
Change in goodwill relating to [Abstract] |  |
Foreign exchange translation | 0.2 | 0.2
Total changes | 0.2 | 0.2
Balance Ending | 12.7 | 12.5
Refractories [Member] |  |
Goodwill [Roll Forward] |  |
Balance Beginning | 43.7 | 44.2
Change in goodwill relating to [Abstract] |  |
Foreign exchange translation | (0.3) | (0.5)
Total changes | (0.3) | (0.5)
Balance Ending | $ 43.4 | $ 43.7

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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)(1)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=120320667&loc=SL49117168-202975 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266 + Details
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- Definition Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267 + Details
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