Note 12 - Net Income Per Share - Computation of Net Income Per Share - Basic & Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Net income	$ 3,643	$ 3,252	$ 2,358	$ 1,930	$ 3,991	$ 2,597	$ 1,826	$ 2,755	$ 2,239	$ 2,403	$ 3,060	$ 1,881	$ 11,183	$ 11,169	$ 9,583
Weighted average outstanding shares of common stock (in shares)													3,679	3,605	3,521
Dilutive effect of stock options (in shares)													165	152	129
Common stock and equivalents (in shares)													3,844	3,757	3,650
Basic (in dollars per share)	$ 0.98	$ 0.88	$ 0.64	$ 0.53	$ 1.10	$ 0.72	$ 0.51	$ 0.77	$ 0.63	$ 0.68	$ 0.87	$ 0.54	$ 3.04	$ 3.10	$ 2.72
Diluted (in dollars per share)													$ 2.91	$ 2.97	$ 2.63

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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