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Fair Value of Financial Instruments (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Transfers in or out of Level 3 | $ 0.0 | $ 0.0
Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Deferred compensation plan assets | 12.9 |
Supplementary pension plan assets | 11.6 |
Interest rate swap | 2.9 |
Money market funds | 0.7 |
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Deferred compensation plan assets | 0.0 |
Supplementary pension plan assets | 0.0 |
Interest rate swap | 0.0 |
Money market funds | 0.7 |
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Deferred compensation plan assets | 12.9 |
Supplementary pension plan assets | 11.6 |
Interest rate swap | 2.9 |
Money market funds | 0.0 |
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Deferred compensation plan assets | 0.0 |
Supplementary pension plan assets | 0.0 |
Interest rate swap | 0.0 |
Money market funds | $ 0.0 |

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- Definition Fair value portion of asset contracts related to interest rate swaps. + References No definition available. + Details
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- Definition Fair value portion of asset contracts related to supplementary pension plan. + References No definition available. + Details
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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References No definition available. + 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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- Definition Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy. + References No definition available. + Details
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