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Debt and Lease Commitments (Parenthetical) (Detail) |  | 12 Months Ended
--- | --- | ---
Jan. 15, 2015 | Dec. 31, 2017 | Dec. 31, 2016
Bank Credit Lines |  |  |
Debt Instrument [Line Items] |  |  |
Line of credit facility, average year-end interest rate |  | 2.50% | 2.40%
Commercial Paper |  |  |
Debt Instrument [Line Items] |  |  |
Line of credit facility, average year-end interest rate |  | 1.70% | 1.10%
Term Notes With Insurance Companies |  |  |
Debt Instrument [Line Items] |  |  |
Line of credit facility, average year-end interest rate |  | 3.40% | 3.50%
Debt instrument maturity | 2030 | 2029 | 2034
Canadian Term Notes With Insurance Companies |  |  |
Debt Instrument [Line Items] |  |  |
Line of credit facility, average year-end interest rate |  | 5.30% | 5.30%
Debt instrument maturity |  | 2018 | 2018
Revolving Credit Agreement Borrowings |  |  |
Debt Instrument [Line Items] |  |  |
Line of credit facility, average year-end interest rate |  | 2.50% | 1.70%

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- Definition The effective interest rate at the end of the reporting period. + 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 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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