Note 8 - Stockholders' Equity - Dividends Per Share (Details) - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2017 |
Mar. 31, 2016 |
Mar. 31, 2015 |
|
| First Quarter [Member] | |||
| Dividends paid (in dollars per share) | $ 0.16 | $ 0.16 | $ 0.15 |
| Second Quarter [Member] | |||
| Dividends paid (in dollars per share) | 0.16 | 0.16 | 0.15 |
| Third Quarter [Member] | |||
| Dividends paid (in dollars per share) | 0.16 | 0.16 | 0.16 |
| Fourth Quarter [Member] | |||
| Dividends paid (in dollars per share) | $ 0.16 | $ 0.16 | $ 0.16 |