Benefit Plans (Stock Option Activity) (Details) - $ / shares	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Stock-Based Compensation [Abstract]
Beginning balance, Outstanding	49,700	64,500
Beginning balance, Weighted Average Exercise Price	$ 9.18	$ 8.67
Exercised	(33,250)	(14,800)
Exercised, Weighted Average Exercise Price	$ 8.63	$ 6.93
Ending balance, Outstanding	16,450	49,700
Ending balance, Weighted Average Exercise Price	$ 10.31	$ 9.18

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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- Definition

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

+ References

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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