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Share-Based Compensation (Stock Option Awards) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options outstanding (in shares)	99,500	42,500
Options Outstanding, Weighted-Avg. Remaining Contractual Life (Years)	7 years 10 months 25 days
Options Outstanding, Weighted-Avg. Exercise Price (in dollars per share)	$ 42.77	$ 44.72
Number of options exercisable (in shares)	19,500
Options Exercisable, Weighted-Avg. Exercise Price (in dollars per share)	$ 41.78
$33.61-$45.30 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options outstanding (in shares)	7,000
Options Outstanding, Weighted-Avg. Remaining Contractual Life (Years)	8 months 12 days
Options Outstanding, Weighted-Avg. Exercise Price (in dollars per share)	$ 35.48
Number of options exercisable (in shares)	7,000
Options Exercisable, Weighted-Avg. Exercise Price (in dollars per share)	$ 35.48
Range of Exercise Prices, lower limit (in dollars per share)	33.61
Range of Exercise Prices, upper limit (in dollars per share)	$ 43.01
$47.61-$50.35 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options outstanding (in shares)	92,500
Options Outstanding, Weighted-Avg. Remaining Contractual Life (Years)	8 years 6 months
Options Outstanding, Weighted-Avg. Exercise Price (in dollars per share)	$ 43.32
Number of options exercisable (in shares)	12,500
Options Exercisable, Weighted-Avg. Exercise Price (in dollars per share)	$ 45.30
Range of Exercise Prices, lower limit (in dollars per share)	42.46
Range of Exercise Prices, upper limit (in dollars per share)	$ 45.30

X

- Definition

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.

+ 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
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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Number of options outstanding, including both vested and non-vested options.

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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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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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