Note 10 - Stock-based Compensation - Allocation of Share-based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2017 |
Mar. 31, 2016 |
Mar. 31, 2015 |
|
| Total cost of stock based compensation charged against income before income tax | $ 1,411 | $ 1,327 | $ 993 |
| Amount of income tax benefit recognized in earnings | 307 | 374 | 373 |
| Amount charged against net income | $ 1,104 | $ 953 | $ 620 |
| Basic (in dollars per share) | $ 0.30 | $ 0.26 | $ 0.18 |
| Diluted (in dollars per share) | $ 0.29 | $ 0.25 | $ 0.17 |