Note 2 - Summary of Significant Accounting Policies -Disaggregation of Revenues by Type (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tour revenues	100.00%	100.00%	100.00%
Guest Ticket [Member]
Tour revenues	91.00%	91.00%	90.00%
Guest Ticket [Member] | Sales Channel, Directly to Consumer [Member]
Tour revenues	45.00%	45.00%	45.00%
Guest Ticket [Member] | Sales Channel, National Geographic [Member]
Tour revenues	17.00%	19.00%	19.00%
Guest Ticket [Member] | Sales Channel, Agencies [Member]
Tour revenues	23.00%	23.00%	22.00%
Guest Ticket [Member] | Sales Channel, Affinity [Member]
Tour revenues	6.00%	4.00%	4.00%
Other Tour [Member]
Tour revenues	9.00%	9.00%	10.00%