Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Earnings per share basic and diluted [Abstract]
Net income applicable to common stock	$ 4,405	$ 4,247
Basic earnings per share computation [Abstract]
Weighted average common shares outstanding (in shares)	3,494,010	3,512,552
Earnings per share - basic (in dollars per share)	$ 1.26	$ 1.21
Diluted earnings per share computation [Abstract]
Weighted average common shares outstanding for basic earnings per share (in shares)	3,494,010	3,512,552
Add: Dilutive effects of restricted stock (in shares)	0	363
Weighted average common shares outstanding for dilutive earnings per share (in shares)	3,494,010	3,512,915
Earnings per share - diluted (in dollars per share)	$ 1.26	$ 1.21
Restricted Stock [Member]
Antidilutive Securities [Abstract]
Antidilutive restricted stock excluded from net income per share calculations (in shares)	6,705	426
Restricted Stock [Member] \| Minimum [Member]
Antidilutive Securities [Abstract]
Antidilutive stock share price range (in dollars per share)	$ 47.81	$ 49.87
Restricted Stock [Member] \| Maximum [Member]
Antidilutive Securities [Abstract]
Antidilutive stock share price range (in dollars per share)	$ 62.93	$ 61.04

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Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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