Share Based Compensation (Share Based Compensation Plans) (Details) - shares	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted	137,258	135,150	150,145
Restricted stock awards forfeited	(2,867)	0	(1,325)
Restricted Stock Unit, Converted to shares and issued to Deferred Compensation Plan	0	217	216
Stock Option, Outstanding as of December 31,	1,639,865	1,690,899	1,546,508	1,481,280
Total Options, Granted, Number of Shares	197,550	192,350	199,100
Stock Options, Exercised, Number of Shares	113,820	40,461	133,872
Stock Options, Forfeited, Number of Shares	18,760	0	0
Stock Options, Expired, Number of Shares	116,004	7,498	0
Stock Issued During Period, Shares, Employee Stock Purchase Plans	41,924	39,384	30,622
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	522,341	764,567	1,127,328
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Director stock awards granted	3,125	3,375	2,625

Number of shares issued pursuant to the terms of a deferred compensation arrangement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Net number of share options (or share units) granted during the period.

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

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Number of shares issued during the period as a result of an employee stock purchase plan.

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Number of new stock issued during the period.

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Number of shares related to Restricted Stock Award forfeited during the period.

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Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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

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