Note 12 - Share-based Compensation (Details) - Summary of Option Transactions (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary of Option Transactions [Abstract]
Outstanding	1,118,058	1,114,058	1,229,834
Outstanding, weighted average exercise price	$ 6.63	$ 5.76	$ 5.62
Granted	397,218	405,768
Granted, weighted average exercise price	$ 8.30	$ 5.72
Exercised	(360,318)	(412,882)
Exercised, weighted average exercise price	$ 5.70	$ 5.37
Lapsed	(20,400)	(62,300)
Lapsed, weighted average exercise price	$ 7.92	$ 5.34
Cancelled	(12,500)	(46,362)
Cancelled, weighted average exercise price	$ 6.43	$ 5.84

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

+ 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)(iv)(4)

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

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

+ References

No definition available.

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

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

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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No definition available.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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No definition available.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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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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Number of share options (or share units) exercised during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

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