Note 10 - Share-based Compensation - Restricted Stock Unit Awards, Valuation Assumptions (Details) |
12 Months Ended | ||
|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2015 |
|
| Volatility | 36.80% | 48.10% | 52.90% |
| Risk-free rate of return | 1.03% | 1.93% | 2.03% |
| Dividend yield | 1.96% | 1.95% | 2.09% |
| Expected average life (years) (Year) | 5 years | 6 years 109 days | 6 years 255 days |
| Restricted Stock Units (RSUs) [Member] | |||
| Volatility | 30.80% | 33.30% | |
| Risk-free rate of return | 0.92% | 0.77% | |
| Dividend yield | 1.97% | 1.99% | |
| Expected average life (years) (Year) | 2 years 14 days | 1 year 273 days | |