Earnings Per Common Share (Details) - $ / shares	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Shares
Basic earnings per share (in shares)	8,669,728	8,633,219
Effect of dilutive securities - stock options (in shares)	17,623	17,920
Diluted earnings per share (in shares)	8,687,351	8,651,139
Per Share Amount
Basic earnings per share (in dollars per share)	$ 0.67	$ 0.47
Effect of dilutive securities - stock options (in dollars per share)	0.00	0.00
Diluted earnings per share (in dollars per share)	$ 0.67	$ 0.47
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities not included in computation of earning per share (in shares)	0	1,320

Refers to the incremental per share amount attributable to share based payment arrangements.

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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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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 average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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