Note 12 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Tour revenues	$ 1,019	$ 100,983	$ 81,991	$ 267,294
Tour revenues, change	(99,964)		$ (185,303)
Tour revenues, percentage change			(69.00%)
Operating income	(26,814)	15,659	$ (59,308)	34,145
Operating income, change	(42,473)		(93,453)
Depreciation and amortization	8,485	6,233	23,728	18,603
Total depreciation and amortization, change	$ 2,252		$ 5,125
Total depreciation and amortization, percentage change	36.00%		28.00%
Total Assets	$ 708,804		$ 708,804		$ 548,658
Total intangibles, net	5,212		5,212		6,396
Total goodwill	22,105		22,105		22,105
Lindblad Segment [Member]
Tour revenues	16	76,581	69,533	217,549
Tour revenues, change	(76,565)		$ (148,016)
Tour revenues, percentage change			(68.00%)
Operating income	(24,835)	12,570	$ (54,287)	31,514
Operating income, change	(37,405)		(85,801)
Depreciation and amortization	7,888	5,812	22,075	17,380
Total depreciation and amortization, change	$ 2,076		$ 4,695
Total depreciation and amortization, percentage change	36.00%		27.00%
Total Assets	$ 637,913		$ 637,913		471,499
Total intangibles, net	2,781		2,781		3,325
Total goodwill	0		0		0
Natural Habitat Segment [Member]
Tour revenues	1,003	24,402	12,458	49,745
Tour revenues, change	(23,399)		$ (37,287)
Tour revenues, percentage change			(75.00%)
Operating income	(1,979)	3,089	$ (5,021)	2,631
Operating income, change	(5,068)		(7,652)
Depreciation and amortization	597	$ 421	1,653	$ 1,223
Total depreciation and amortization, change	$ 176		$ 430
Total depreciation and amortization, percentage change	42.00%		35.00%
Total Assets	$ 70,891		$ 70,891		77,159
Total intangibles, net	2,431		2,431		3,071
Total goodwill	$ 22,105		$ 22,105		$ 22,105