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Pension and Other Postretirement Benefits - Additional Information (Detail) |  | 9 Months Ended
--- | --- | ---
Apr. 18, 2017 USD ($) | Sep. 30, 2017 USD ($) Installments
Retirement Benefits [Abstract] |  |
Cash contribution term to pension plan |  | 30 months
Number of installments | Installments |  | 3
Minimum required cash contribution to pension plan |  | $ 50,000,000
Aggregate cash cash contribution to pension plan |  | $ 150,000,000
First payment to pension plan | $ 50,000,000 |

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- Definition Minimum required cash contribution to pension plan. + References No definition available. + Details
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- Definition Amount of payment for pension and other postretirement benefits. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585 + Details
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