| Note 9 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Millions | 3 Months Ended | |||
|---|---|---|---|---|
| Mar. 31, 2023 | Mar. 31, 2022 | Jan. 12, 2016 | Jul. 28, 2015 | |
| Common Stock, Dividends, Per Share, Declared (in dollars per share) | $ 0.20 | $ 0.20 | ||
| Dividends, Common Stock | $ 2.3 | $ 2.3 | ||
| Stock Repurchase Program, Authorized Amount | $ 70.0 | $ 15.0 | ||
| Stock Repurchase Program, Remaining Authorized Repurchase Amount | $ 21.9 | |||
| X | ||||||||||
| 
- Definition Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Amount of stock repurchase plan authorized. No definition available. 
 | 
| X | ||||||||||
| 
- Definition Amount remaining of a stock repurchase plan authorized. No definition available. 
 |