Note 9 - Share-based Compensation and Cash-based Incentive Compensation - Summary of Compensation Expense Related to Share-Based Awards and Cash-Based Awards (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | |||||
|---|---|---|---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
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| Share-based compensation | $ 1,259 | $ 1,215 | $ 1,181 | $ 2,434 | |||
| Total charged to operating income | 2,904 | 3,149 | 4,798 | 7,900 | |||
| General and Administrative Expense [Member] | |||||||
| Share-based compensation | 1,259 | 1,215 | 1,181 | 2,434 | |||
| Lease operating expense (1) | [1] | 1,243 | 1,391 | 3,338 | 4,063 | ||
| Lease Operating Expense [Member] | |||||||
| Lease operating expense (1) | [1] | $ 402 | $ 543 | $ 279 | $ 1,403 | ||
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| X | ||||||||||
- Definition Amount of noncash expense for share-based payment arrangement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Cash-based incentive compensation charged to operating income (loss). No definition available.
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| X | ||||||||||
- Definition The total amount of share-based and cash-based incentive compensation charged to operating income. No definition available.
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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