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Inventories - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Inventories [Line Items] |  |  |
After-tax LIFO (income) expense | $ (0.3) | $ 0.3 | $ 1.1

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- Definition Inventories [Line Items] + References No definition available. + Details
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- Definition The effect of liquidating LIFO (last in first out) inventory layers on income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(6)(c)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section S99 -Paragraph 3 -Subparagraph (SAB Topic 11.F) -URI http://asc.fasb.org/extlink&oid=27011343&loc=d3e100079-122729 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(6)(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(6)(a)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section S99 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=27011343&loc=d3e100079-122729 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section S50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6386917&loc=d3e99609-122727 + Details
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