Note 2 - Summary of Significant Accounting Policies - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Prepaid tour expenses	$ 26,123	$ 20,605
Marine operating supplies	5,438	9,961
Other	25,597	21,173
Total prepaid expenses and other current assets	$ 57,158	$ 53,704