Note 17 - Subsequent Events (Details Textual) - Class Vessel [Member] - Ulstein Verft [Member] kr in Millions	Feb. 25, 2019 USD ($)	Nov. 30, 2017 NOK (kr)	Nov. 30, 2017 USD ($)
Vessel, Contract Price		kr 1,066	$ 134,600,000
Subsequent Event [Member]
Vessel, Contract Price	$ 1,291,000,000