Note 13 - Stock-based Compensation and Purchase Plans - Assumptions Used to Estimate Fair Values (Details) - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Risk-free interest rates | 3.69% | 3.69% | 4.52% |
| Expected life of option grants (in years) (Year) | 3 years | 3 years | 3 years |
| Expected volatility of underlying stock | 34.70% | 34.10% | 29.50% |
| Expected quarterly dividends (per share) (in dollars per share) | $ 0.32 | $ 0.32 | $ 0.28 |