Note 2 - Summary of Significant Accounting Policies - Disaggregation of Revenues by Type (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Tour revenues	100.00%	100.00%	100.00%
Guest Ticket [Member]
Tour revenues	93.00%	89.00%	91.00%
Guest Ticket [Member] | Sales Channel, Directly to Consumer [Member]
Tour revenues	56.00%	41.00%	45.00%
Guest Ticket [Member] | Sales Channel, National Geographic [Member]
Tour revenues	14.00%	18.00%	17.00%
Guest Ticket [Member] | Sales Channel, Agencies [Member]
Tour revenues	18.00%	25.00%	23.00%
Guest Ticket [Member] | Sales Channel, Affinity [Member]
Tour revenues	5.00%	5.00%	6.00%
Other Tour [Member]
Tour revenues	7.00%	11.00%	9.00%