Note 3 - Revenues - Disaggregation of Revenues by Type (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Tour Revenues	100.00%	100.00%	100.00%	100.00%
Guest Ticket [Member]
Tour Revenues	64.00%	93.00%	89.00%	91.00%
Guest Ticket [Member] | Sales Channel, Directly to Consumer [Member]
Tour Revenues	32.00%	48.00%	41.00%	44.00%
Guest Ticket [Member] | Sales Channel, National Geographic [Member]
Tour Revenues	0.00%	14.00%	18.00%	16.00%
Guest Ticket [Member] | Sales Channel, Agencies [Member]
Tour Revenues	26.00%	21.00%	24.00%	23.00%
Guest Ticket [Member] | Sales Channel, Affinity [Member]
Tour Revenues	6.00%	10.00%	6.00%	8.00%
Other Tour [Member]
Tour Revenues	36.00%	7.00%	11.00%	9.00%