Note 2 - Summary of Significant Accounting Policies - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Prepaid tour expenses	$ 10,337	$ 5,630
Prepaid marketing, commissions and other expenses	4,791	3,504
Prepaid client insurance	4,304	2,283
Prepaid air expense	4,051	3,817
Prepaid port agent fees	2,012	530
Prepaid corporate insurance	1,397	1,105
Prepaid income taxes	202	145
Total prepaid expenses	$ 27,094	$ 17,014