Note 16 - Related Parties (Details Textual) - USD ($) $ in Millions  | 
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020  | 
Dec. 31, 2019  | 
Dec. 31, 2018  | 
|
| Airplane Services [Member] | |||
| Related Party Transaction, Amounts of Transaction | $ 0.3 | $ 1.2 | $ 1.3 | 
| Marine Transportation and Logistic Services [Member] | |||
| Related Party Transaction, Amounts of Transaction | 0.1 | 0.1 | 0.1 | 
| Repayments of Related Party Debt | $ 14.4 | $ 22.8 | 21.0 | 
| CEO and Largest Shareholder [Member] | Senior Second Lien Note Issuance [Member] | |||
| Debt Instrument, Face Amount | $ 8.0 | ||
| X | ||||||||||
- Definition Face (par) amount of debt instrument at time of issuance. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
- Definition Amount of transactions with related party during the financial reporting period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
- Definition The cash outflow for the payment of a long-term borrowing made from a related party where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth. Alternate caption: Payments for Advances from Affiliates. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
- Details 
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| X | ||||||||||
- Details 
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| X | ||||||||||
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| X | ||||||||||
- Details 
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