Fair Value Measurements (Details) - Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member] - Management [Member] - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Schedule of Trading Security [Line Items] | ||
| Maximum percentage of participants' compensation which is deferrable (as a percent) | 100.00% | |
| Balance of the plan which was fully funded | $ 4.6 | $ 5.4 |
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- Definition Represents the maximum percentage of participants' compensation that is deferrable by participants under the deferred compensation plan. No definition available.
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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. No definition available.
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- Definition Carrying amount as of the balance sheet date of assets held under deferred compensation agreements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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