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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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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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Price of a single share of a number of saleable stocks of a company.

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The maximum awards to each employee under the plan per period.

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The percentage of the participant's base salary that is used to determine the share-based compensation.

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No definition available.

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Note 8 - Equity Plans (Details Textual) - USD ($)				3 Months Ended
Note 8 - Equity Plans (Details Textual) - USD ($)	Mar. 13, 2018	Mar. 13, 2017	Jul. 01, 2016	Mar. 31, 2018	Mar. 31, 2017
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				55,532
Restricted Stock Units (RSUs) [Member] \| Senior Management Stock Incentive Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			5 years
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Participant's Base Salary			10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Amount Per Employee			$ 17,500
Restricted Stock Units (RSUs) [Member] \| Non-Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	3,496	3,501
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				1 year
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				1,000,000
Share Price	$ 22.88				$ 19.99