Note 1 - Basis of Presentation and Accounting Policies - Property and Equipment Useful Life (Details)
|6 Months Ended|
Jun. 30, 2018
|Wind Farm Utility Vessel [Member]|
|Estimated useful life (Year)||10 years|
|Offshore Support Vessels [Member]|
|Estimated useful life (Year)||20 years|
Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.
No definition available.