Note 6 - Revenues - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Balance	$ 701	$ 813	$ 585	$ 602
Unbilled	980	960	1,565	1,645
Billings	(579)	(664)	(1,048)	(1,138)
Balance	1,102	1,109	1,102	1,109
Balance			3,200
Billings	579	664	1,048	1,138
Balance	5,400		5,400
Deferred Membership Dues [Member]
Billings	(2,915)	(2,254)	(5,448)	(4,641)
Balance	4,122	4,018	3,196	3,153
Billings	2,915	2,254	5,448	4,641
Revenue recognized	(1,661)	(1,496)	(3,268)	(3,018)
Balance	5,376	4,776	5,376	4,776
Customer Advance Deposits [Member]
Billings	(479)	(140)	(711)	(395)
Balance	752	630	674	553
Billings	479	140	711	395
Revenue recognized	(447)	(118)	(601)	(296)
Balance	$ 784	$ 652	$ 784	$ 652