Stock-based Compensation (Schedule of SARs Oustanding) (Details)	12 Months Ended
Dec. 31, 2018 $ / shares shares
SARs
Forfeited	(564)
SARs [Member]
SARs
Balance at December 31, 2017	281,067
Exercised	(43,946)
Forfeited
Balance at December 31, 2018	237,121
Exercisable at December 31, 2018	237,121
Weighted Average Exercise Price
Balance at December 31, 2017 \| $ / shares	$ 29.14
Exercised \| $ / shares	25.26
Forfeited \| $ / shares
Balance at December 31, 2018 \| $ / shares	29.86
Exercisable at December 31, 2018 \| $ / shares	$ 29.86

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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No definition available.

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- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

+ References

No definition available.

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- Definition

Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

+ References

No definition available.

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- Definition

Number of shares (or other type of equity) forfeited during the period.

+ References

No definition available.

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- Definition

Number of share options (or share units) exercised during the current period.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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