Stock Based Compensation Schedule of Other Stock Option Plan Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Stock Options Granted (in shares)	53,560	55,069.98	59,008.7
Fair Value of Options Granted, Weighted Average Grant Date (in dollars per share)	$ 5.58	$ 5.43	$ 5.89
Dividend Yield	3.26%	2.98%	2.72%
Expected Volatility	22.58%	21.55%	21.40%
Risk Free Interest Rate	2.63%	2.68%	2.25%
Expected Lives (in years)	8 years 8 months 5 days	6 years 11 months 23 days	6 years 10 months 17 days
Amount Expensed During the Year	$ 316	$ 322	$ 351
Compensation Costs for Non-vested Awards Not Yet Recognized	$ 487	$ 504	$ 528
Weighted Average Expected Vesting Period (in years)	2 years 26 days	2 years 8 months 27 days	2 years 7 months 2 days
Proceeds From Stock Options Exercised	$ 1,792	$ 2,255	$ 1,190
Tax Benefits Related to Stock Options Exercised	227	240	168
Intrinsic Value of Stock Options Exercised	$ 1,073	$ 1,552	$ 825

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Amount of tax benefit from exercise of option under share-based payment arrangement.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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Amount of noncash expense for share-based payment arrangement.

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Gross number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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