Note 10 - Share-based Compensation - Stock Options, Valuation Assumptions (Details) |
6 Months Ended | 12 Months Ended |
---|---|---|
Dec. 31, 2019 |
Jun. 30, 2019 |
|
Employees [Member] | ||
Volatility | 30.80% | |
Risk-free rate of return | 1.84% | |
Dividend yield | 4.56% | |
Expected average life (years) (Year) | 6 years 255 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 |