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Commitments and Contingencies - Collective Bargaining Agreements (Detail) - Withdrawal from Multiemployer Defined Benefit Plan - Central States Plan - USD ($) $ in Millions | 36 Months Ended | 52 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2017 | Sep. 30, 2017 | Jan. 31, 2016 | Jul. 31, 2014 | Oct. 09, 2013 | Dec. 31, 2011
Loss Contingencies [Line Items] |  |  |  |  |  |
Amount of withdrawal liability |  |  | $ 32.9 | $ 39.6 |  | $ 32.6
Payment of withdrawal liability assessment amount | $ 22.3 |  |  |  |  |
Acquired Company |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Amount of withdrawal liability |  |  | $ 4.8 |  | $ 4.8 |
Payment of withdrawal liability assessment amount |  | $ 4.0 |  |  |  |
Amount of withdrawal liability, amount suggested by Plan which is different than amount recorded by company |  |  |  |  | $ 6.9 |
Minimum |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Amount of withdrawal liability | 42.2 | 42.2 |  |  |  |
Maximum |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Amount of withdrawal liability | $ 48.2 | $ 48.2 |  |  |  |

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- Definition Amount of cash outflow reducing loss contingency liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349 + Details
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