Note 6 - Asset Retirement Obligation (Details Textual) - USD ($) |
3 Months Ended | 9 Months Ended | ||||
|---|---|---|---|---|---|---|
Sep. 30, 2020 |
Sep. 30, 2019 |
Sep. 30, 2020 |
Sep. 30, 2019 |
Dec. 31, 2019 |
Mar. 17, 2017 |
|
| Asset Retirement Obligations, Noncurrent, Total | $ 827,000 | $ 827,000 | $ 790,000 | $ 700,000 | ||
| Accretion Expense, Including Asset Retirement Obligations, Total | 12,000 | $ 12,000 | 36,000 | $ 34,000 | ||
| Contributions to Trust Fund, Amount | $ 670,000 | $ 670,000 | ||||
| X | ||||||||||
- Definition The carrying amount of contributions made to a trust fund which are available for withdrawal when needed. No definition available.
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| X | ||||||||||
- Definition Amount of accretion expense, which includes, but is not limited to, accretion expense from asset retirement obligations, environmental remediation obligations, and other contingencies. No definition available.
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| X | ||||||||||
- Definition Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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