Note 5 - Revenues - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Balance at beginning of period	$ 599	$ 578
Balance at beginning of period	3,600
Unbilled membership dues	620	640
Billings	472	458
Billings	(472)	(458)
Balance at end of period	747	760
Balance at end of period	4,900
Deferred Membership Dues [Member]
Balance at beginning of period	3,643	3,363
Billings	3,104	3,294
Billings	(3,104)	(3,294)
Revenue recognized	(1,847)	(1,714)
Balance at end of period	4,900	4,943
Customer Advance Deposits [Member]
Balance at beginning of period	965	795
Billings	757	388
Billings	(757)	(388)
Revenue recognized	(640)	(263)
Balance at end of period	$ 1,082	$ 920