Note 7 - Leases (Details Textual)  | 
Dec. 31, 2020  | 
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| Office Lease [Member] | |
| Lessee, Operating Lease, Renewal Term (Year) | 10 years | 
| Lessee, Operating Lease, Discount Rate | 9.75% | 
| Pipeline Right-of-way Contracts [Member] | |
| Lessee, Operating Lease, Renewal Term (Year) | 10 years | 
| Lessee, Operating Lease, Term of Contract (Year) | 10 years | 
| Land Acquired in Mobile Bay Properties Acquisition [Member] | |
| Lessee, Operating Lease, Renewal Term (Year) | 5 years | 
| Other Leases [Member] | |
| Lessee, Operating Lease, Discount Rate | 10.75% | 
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- Definition Discount rate used by lessee to determine present value of operating lease payments. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
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- Definition Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Definition Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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