Note 11 - Share-based Compensation - Stock Options, Valuation Assumptions (Details) |
9 Months Ended | 12 Months Ended |
|---|---|---|
Mar. 31, 2020 |
Jun. 30, 2019 |
|
| Employees [Member] | ||
| Volatility | 30.80% | |
| Risk-free rate of return | 1.62% | |
| Dividend yield | 4.42% | |
| Expected average life (years) (Year) | 5 years 328 days | |
| Independent Directors [Member] | ||
| Volatility | 30.80% | 31.30% |
| Risk-free rate of return | 1.55% | 2.80% |
| Dividend yield | 3.97% | 3.24% |
| Expected average life (years) (Year) | 5 years 109 days | 5 years |