Note 5 - Revenues - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Balance at beginning of period	$ 747	$ 760	$ 599	$ 578
Balance at beginning of period			3,600
Unbilled membership dues	849	965	1,470	1,605
Billings	513	580	986	1,038
Billings	(513)	(580)	(986)	(1,038)
Balance at end of period	1,083	1,145	1,083	1,145
Balance at end of period	5,700		5,700
Deferred Membership Dues [Member]
Balance at beginning of period	4,900	4,943	3,643	3,363
Billings	2,671	2,633	5,775	5,927
Billings	(2,671)	(2,633)	(5,775)	(5,927)
Revenue recognized	(1,834)	(1,794)	(3,681)	(3,508)
Balance at end of period	5,737	5,782	5,737	5,782
Customer Advance Deposits [Member]
Balance at beginning of period	1,082	920	965	795
Billings	1,115	915	1,820	1,303
Billings	(1,115)	(915)	(1,820)	(1,303)
Revenue recognized	(1,048)	(843)	(1,636)	(1,106)
Balance at end of period	$ 1,149	$ 992	$ 1,149	$ 992