| Note 7 - Share-based Awards and Cash-based Awards - Summary of Incentive Compensation Expense Under Share-based Payment Arrangements (Details) - USD ($) $ in Thousands | 3 Months Ended | |
|---|---|---|
| Mar. 31, 2021 | Mar. 31, 2020 | |
| Share-based compensation expense | $ 454 | $ 1,048 | 
| Restricted Stock Units (RSUs) [Member] | ||
| Share-based compensation expense | 338 | 978 | 
| Restricted Stock [Member] | ||
| Share-based compensation expense | $ 116 | $ 70 | 
| X | ||||||||||
| 
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
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- Details 
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| X | ||||||||||
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- Details 
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