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Litigation, Claims and Contingencies - Summary of Asbestos Claims Activity (Details) - Claim Claim in Thousands | 3 Months Ended | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2016
Ashland [Member] |  |  |  |  |
Asbestos claims [Roll Forward] |  |  |  |  |
Open claims - beginning of year | 53 | 54 | 54 | 57 | 60
New claims filed | 1 | 1 | 2 | 2 | 2
Claims settled | (1) | 0 | (1) | (1) | 0
Claims dismissed | 0 | (1) | (2) | (4) | (5)
Open claims - end of period | 53 | 54 | 53 | 54 | 57
Hercules [Member] |  |  |  |  |
Asbestos claims [Roll Forward] |  |  |  |  |
Open claims - beginning of year | 13 | 12 | 12 | 15 | 20
New claims filed |  |  | 2 | 1 | 1
Claims dismissed | (1) |  | (1) | (4) | (6)
Open claims - end of period | 12 | 12 | 13 | 12 | 15

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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition Number of claims dismissed. + References No definition available. + Details
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- Definition Number of claims settled. + References No definition available. + Details
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- Definition The total number of new claims filed pertaining to a loss contingency during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349 + Details
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- Definition Number of pending claims pertaining to a loss contingency. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349 + Details
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- Details
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