Note 4 - Stock Options and Restricted Stock Awards (Details Textual) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Share-Based Payment Arrangement, Option [Member] | ||||
| Share-Based Payment Arrangement, Expense | $ 6.8 | $ 7.2 | $ 21.3 | $ 22.0 |
| Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | 18.2 | $ 18.2 | ||
| Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition | 2 years 4 months 24 days | |||
| Restricted Stock [Member] | ||||
| Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 19.8 | $ 19.8 | ||
| Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition | 1 year 6 months | |||