Note 6 - Stock-Based Compensation (Detail) - Changes In Shares Under Option Plans (USD $)	1 Months Ended	3 Months Ended
Jan. 31, 2013	Mar. 31, 2013	Mar. 31, 2012
Beginning Balance	652,064	652,064	831,393
Beginning Balance (in Dollars per share)	$ 11.12	$ 11.12	$ 11.19
Issued	3,000	3,000
Issued (in Dollars per share)		$ 22.03
Exercised		(47,717)	(31,465)
Exercised (in Dollars per share)		$ 9.80	$ 13.72
Forfeited		(300)
Forfeited (in Dollars per share)		$ 6.34
Expired		(14,550)	(26,655)
Expired (in Dollars per share)		$ 11.87	$ 15.32
Ending Balance		592,497	773,273
Ending Balance (in Dollars per share)		$ 11.26	$ 10.94

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

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-Name Accounting Standards Codification

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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.

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

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including 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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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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Number of share options (or share units) exercised during the current period.

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