Note 7 - Stock-based Compensation and Other Plans (Details Textual) - The 2008 Plan [Member] - USD ($)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	340,750
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	25,000
Employee Stock Option [Member]
Allocated Share-based Compensation Expense, Total	$ 43,000	$ 62,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	16,000	23,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total	459,000
Restricted Stock [Member]
Allocated Share-based Compensation Expense, Total	6,000	12,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	2,000	$ 5,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total	$ 10,000

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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-Topic 718
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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

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.

+ References

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- Definition

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

+ References

No definition available.

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