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Note 11 - Summary of Information about Stock Options Outstanding (Details)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Range One [Member]
Options Outstanding Number of Options (in shares) | shares	24,000
Options Outstanding Weighted Average Remaining Contractual Life	4 years 91 days
Options Outstanding Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 24.15
Exercisable and Outstanding (in shares) | shares	24,000
Options Exercisable Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 24.15
Range Two [Member]
Options Outstanding Number of Options (in shares) | shares	2,000
Options Outstanding Weighted Average Remaining Contractual Life	131 days
Options Outstanding Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 28.31
Exercisable and Outstanding (in shares) | shares	2,000
Options Exercisable Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 28.31
Range Three [Member]
Options Outstanding Number of Options (in shares) | shares	2,000
Options Outstanding Weighted Average Remaining Contractual Life	1 year 149 days
Options Outstanding Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 34.77
Exercisable and Outstanding (in shares) | shares	2,000
Options Exercisable Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 34.77
Options Outstanding Number of Options (in shares) | shares	28,000
Options Outstanding Weighted Average Remaining Contractual Life	3 years 281 days
Options Outstanding Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 25.21
Exercisable and Outstanding (in shares) | shares	28,000
Options Exercisable Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 25.21

X

- Definition

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.

+ 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 (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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X

- Definition

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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X

- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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X

- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ 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 (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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X

- Definition

Weighted average remaining contractual term for option awards outstanding, 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 (e)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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