Note 11 - Commitments and Contingencies (Details Textual) kr in Millions, $ in Millions |
3 Months Ended | 9 Months Ended | |||||||
---|---|---|---|---|---|---|---|---|---|
Sep. 30, 2019
USD ($)
|
Sep. 30, 2018
USD ($)
|
Sep. 30, 2019
USD ($)
|
Sep. 30, 2018
USD ($)
|
Mar. 31, 2019
USD ($)
|
Feb. 28, 2019
NOK (kr)
|
Dec. 31, 2018
USD ($)
|
Dec. 31, 2017
NOK (kr)
|
Dec. 31, 2017
USD ($)
|
|
National Geographic [Member] | |||||||||
Royalty Expense | $ 1.7 | $ 1.2 | $ 4.8 | $ 3.3 | |||||
Accounts Payable and Other Accrued Liabilities, Current | 1.7 | 1.7 | $ 1.0 | ||||||
World Wildlife Fund [Member] | |||||||||
Royalty Expense | $ 0.3 | $ 0.3 | $ 0.7 | $ 0.6 | |||||
Class Vessel [Member] | Ulstein Verft [Member] | |||||||||
Vessel, Contract Price | kr 1,066 | $ 134.6 | |||||||
Foreign Exchange Contract [Member] | Ulstein Verft [Member] | |||||||||
Vessel, Contract Price | $ 153.5 | kr 1,291 |