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Stock Options and Stock Appreciation Rights - Options (Details) - USD ($) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Apr. 05, 2012
Employee Stock Option |  |  |  |
Stock option details |  |  |  |
Shares available for future grants |  |  |  | 800,000
Maximum exercisable period for granted share-based compensation | 10 years |  |  |
Black-Scholes-Merton option valuation model assumptions |  |  |  |
Expected Life (Years) |  | 7 years |  |
Dividend yield (as a percent) |  | 3.08% |  |
Interest rate (as a percent) |  | 1.94% |  |
Volatility (as a percent) |  | 37.78% |  |
Stock option activity |  |  |  |
Options outstanding at the beginning of the period (in shares) | 461,822 |  |  |
Less: |  |  |  |
Options exercised (in shares) | (46,444) |  |  |
Options forfeited (in shares) | (31,513) |  |  |
Options outstanding at the end of the period (in shares) | 383,865 | 461,822 |  |
Options fully vested and exercisable at the end of the period (in shares) | 232,143 |  |  |
Stock Options, Weighted average exercise price |  |  |  |
Options outstanding at the beginning, weighted average exercise price (in dollars per share) | $ 29.67 |  |  |
Less: |  |  |  |
Options exercised, weighted average exercise price (in dollars per share) | 25.12 |  |  |
Options forfeited, weighted average exercise price (in dollars per share) | 24.52 |  |  |
Options outstanding at the end, weighted average exercise price (in dollars per share) | 30.65 | $ 29.67 |  |
Options fully vested and exercisable at the end, weighted average exercise price (in dollars per share) | $ 27.80 |  |  |
Stock Options, Weighted average remaining contractual term (years) |  |  |  |
Options outstanding at the end, weighted average remaining contractual term (years) | 3 years 5 months 1 day |  |  |
Options fully vested and exercisable at the end, weighted average remaining contractual term (years) | 1 year 11 months 15 days |  |  |
Stock Options, Aggregate intrinsic value |  |  |  |
Options outstanding at the end, aggregate intrinsic value | $ 9,088,000 |  |  |
Options fully vested and exercisable at the end, aggregate intrinsic value | 6,157,000 |  |  |
Stock-based compensation expense | 330,000 | $ 449,000 | $ 506,000 |
Stock-based compensation cost, unrecognized | $ 507,000 |  |  |
Stock-based compensation cost, unrecognized, weighted-average period of recognition | 1 year 3 months 18 days |  |  |
Other information pertaining to option activity |  |  |  |
Weighted average grant date fair value of stock options granted (in dollars per share) |  | $ 11.24 | $ 10.20 |
Total fair value of stock options vested | $ 514,000 | $ 514,000 | $ 1,308,000 |
Total intrinsic value of stock options exercised | $ 1,060,000 | $ 1,670,000 | $ 2,536,000 |
Incentive Stock Options to 10 Percent Shareholders |  |  |  |
Stock option details |  |  |  |
Maximum exercisable period for granted share-based compensation | 5 years |  |  |

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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (f)(2)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
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