Earnings Per Common Share (Calculations of Basic and Diluted Earnings per Common Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Distributed earnings allocated to shareholders	$ 5,409	$ 3,972	$ 15,532	$ 11,184
Undistributed earnings allocated to shareholders	7,246	6,865	16,638	18,134
Net earnings allocated to shareholders	$ 12,655	$ 10,837	$ 32,170	$ 29,318
Weighted-average number of common shares outstanding - basic	19,325,457	18,056,202	18,875,290	18,043,692
Effect of potentially dilutive shares	141,408	157,331	128,797	156,267
Total weighted-average diluted shares outstanding	19,466,865	18,213,533	19,004,087	18,199,959
Earnings per common share - basic	$ 0.65	$ 0.60	$ 1.70	$ 1.62
Earnings per common share - diluted	$ 0.65	$ 0.60	$ 1.69	$ 1.61
Anti-dilutive shares excluded from computation of EPS	5,541	163	2,193	270

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 total amount of dividends declared in the period for each class of stock and the contractual amount of dividends (or interest on participating income bonds) that must be paid for the period (for example, unpaid cumulative dividends). Dividends declared in the current period do not include dividends declared in respect of prior-period unpaid cumulative dividends. Preferred dividends that are cumulative only if earned are deducted only to the extent that they are earned.

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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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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders.

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The earnings that is allocated to common stock and participating securities to the extent that each security may share in earnings as if all of the earnings for the period had been distributed. Includes the adjustments resulting from the assumption that dilutive securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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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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