Annual cash retainer fee paid to each non-employee member of the Board of Directors.

No definition available.

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Annual Elected Retainer Fees, Percent

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Share-based Compensation Arrangement by Share-based Payment Award, Annual Award Vesting Rights, Percentage

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No definition available.

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Share-based Compensation Arrangement by Share-based Payment Award, Options, Vesting Period Start, Period After Grant

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No definition available.

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Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Aggregate Exercise Price

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No definition available.

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Share-based Compensation, Net of Taxes

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Share-based Compensation, Net of Taxes, Per Share

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No definition available.

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Share-based Compensation, Period of Recognition

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Share-based Compensation, Weighted Average Period of Recognition

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No definition available.

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- Definition

Aggregate proceeds received by the entity during the annual period from exercises of stock or unit options and conversion of similar instruments granted under equity-based payment arrangements.

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Unrecognized cost of unvested share-based compensation awards.

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- Definition

The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

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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- Definition

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

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- Definition

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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No definition available.

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Number of additional shares authorized for issuance under an established share-based compensation plan.

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No definition available.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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- Definition

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

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No definition available.

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- Definition

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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- Definition

An excess of the fair value of the modified award over the fair value of the award immediately before the modification.

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- Definition

The number of employees affected by the modification of an equity-based compensation plan.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

+ References

No definition available.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
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-Subparagraph (SAB Topic 14.D.2)
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Number of new stock issued during the period.

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-Name Accounting Standards Codification
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-SubTopic 10
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-Name Accounting Standards Codification
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
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Number of share options (or share units) exercised during the current period.

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Number of treasury shares (units) reissued during the period, excluding reissuance of shares (units) held in treasury used to satisfy equity-based compensation obligations exercised by the holders of such rights. Upon reissuance of shares (units) from treasury, either the common or preferred stock (unit) reissued is outstanding.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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Stock Options, Stock Grants and New Stock (Narrative) (Details)									12 Months Ended
	May 18, 2017 USD ($) shares	Feb. 08, 2017 $ / shares shares	May 05, 2016 USD ($) $ / shares shares	Feb. 19, 2016 $ / shares shares	May 12, 2015 USD ($) shares	Feb. 10, 2015 $ / shares shares	Jan. 05, 2015 $ / shares shares	Feb. 20, 2014	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, weighted average fair value (dollars per share) \| $ / shares									$ 6.41	$ 6.24	$ 6.57
Exercised (shares)									25,632	0	666
Shares of common stock purchased									0	29,500	100,400
Options exercisable (shares)									119,861
Options exercisable, weighted average exercise price (dollars per share) \| $ / shares									$ 12.45
Share-based compensation expense \| $									$ 638,416	$ 459,473	$ 521,695
Issuance of shares of common stock from the treasury (in shares)									58,532	62,124	26,118
Issuance of common stock (shares)									0	0	0
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercised (shares)									25,632		666
Shares of common stock purchased									20,243
Cash received from exercise of stock options \| $											$ 8,302
Option exercises, aggregate exercise price \| $									$ 296,050		$ 8,302
Options exercisable (shares)									119,861	129,762	88,025
Options exercisable, weighted average exercise price (dollars per share) \| $ / shares									$ 12.45	$ 12.12	$ 11.85
Share-based compensation expense \| $									$ 80,966	$ 135,085	$ 278,341
Total unrecognized compensation cost \| $									$ 86,280
Share-based compensation, weighted average period of recognition (years)									1 year 10 months 23 days
2011 Plan [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (shares)						32,532
Options granted, weighted average exercise price (dollars per share) \| $ / shares						$ 16.01
Options granted, weighted average fair value (dollars per share) \| $ / shares						$ 6.39
Risk free interest rate (percent)						2.00%
Expected volatility rate (percent)						46.00%
Expected life (years)						7 years
Expected dividend yield (percent)						2.00%
2005 Stock Awards Plan [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting rate (percent)								20.00%
2005 Stock Awards Plan [Member] \| Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense \| $									$ 557,450	324,388	243,354
Total unrecognized compensation cost \| $									$ 1,073,914
Share-based compensation, weighted average period of recognition (years)									2 years 1 month 15 days
Share-based compensation expense, period of recognition (years)									60 months
Share-based compensation expense, net of taxes \| $									$ 354,538	$ 206,311	$ 154,773
Share-based compensation expense, net of taxes, (dollars per share) \| $ / shares									$ 0.04	$ 0.02	$ 0.02
2015 Stock Awards Plan [Member] \| Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting rate (percent)									20.00%
Granted (shares)		44,687	42,193	50,062
Granted, weighted average grant date fair value (dollars per share) \| $ / shares		$ 12.30	$ 8.05	$ 7.51
Period after grant date, awards vesting begins (years)									1 year
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized									250,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Number of Employees Affected		8	5
External Consultants [Member] \| 2005 Stock Awards Plan [Member] \| Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (shares)							3,000
Granted, weighted average grant date fair value (dollars per share) \| $ / shares							$ 17.95
Non Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of shares of common stock from the treasury (in shares)	24,209		40,991		8,216
Annual cash retainer fees \| $	$ 287,500		$ 330,000		$ 118,750
Restricted Stock [Member] \| Non Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum annual retainer percent									100.00%
May 5, 2016 [Member] \| 2015 Stock Awards Plan [Member] \| Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost \| $									$ 75,756
February 8, 2017 [Member] \| 2015 Stock Awards Plan [Member] \| Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost \| $									$ 67,180