Note 8 - Restricted Deposits for ARO (Details Textual) - USD ($) $ in Thousands  | 
Dec. 31, 2020  | 
Dec. 31, 2019  | 
|---|---|---|
| Restricted Deposits for Asset Retirement Obligations [Member] | ||
| Escrow Deposit | $ 13,900 | |
| Other Noncurrent Liabilities [Member] | ||
| Escrow Liability, Noncurrent | $ 11,103 | $ 0 | 
| X | ||||||||||
- Definition The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
- Definition Amount of liabilities classified as escrow, due after one year or the normal operating cycle, if longer. No definition available. 
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- Details 
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- Details 
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