Note 16 - Quarterly Financial Data - Unaudited - Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Tour revenues	$ 70,609	$ 87,242	$ 69,473	$ 82,410	$ 63,221	$ 84,584	$ 55,571	$ 63,128	$ 309,734	$ 266,504	$ 242,346
Gross profit	31,511	42,278	35,663	46,539	27,475	46,104	26,874	30,525	155,991	130,978	123,369
Net income (loss)	$ (4,552)	$ 5,346	$ (159)	$ 10,917	$ (15,019)	$ 9,443	$ (2,578)	$ 625	$ 11,552	$ (7,529)	$ 5,059
Diluted (in dollars per share)	$ (0.10)	$ 0.11	$ 0	$ 0.24	$ (0.36)	$ 0.20	$ (0.06)	$ 0.01	$ 0.24	$ (0.19)	$ 0.10
Diluted earnings (loss) per share (in dollars per share)	$ (0.10)	$ 0.11	$ 0	$ 0.24	$ (0.36)	$ 0.20	$ (0.06)	$ 0.01	$ 0.24	$ (0.19)	$ 0.10