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Schedule of Measurement Dates (Detail) | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016
Benefit Obligation |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Measurement Dates | Dec. 31, 2017 | Dec. 31, 2016
Fair Value Of Plan Assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Measurement Dates | Dec. 31, 2017 | Dec. 31, 2016

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- Definition Month-end measurement date applicable when an accounting policy election is made to measure plan assets and benefit obligations as of the month-end that is closest to the fiscal year-end, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (u) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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- Details
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