Note 1 - Description of Business and Summary of Significant Accounting Policies - Basic and Diluted Net Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Net earnings	$ 24,821	$ 12,795
Undistributed earnings	21,444	9,428
Common Class A [Member]
Net earnings	4,076	2,089
Less dividends declared	515	515
Undistributed earnings	$ 3,561	$ 1,574
Weighted-average shares outstanding, basic and diluted (in shares)	2,145	2,145
Net earnings per share, basic and diluted (in dollars per share)	$ 1.90	$ 0.97
Common Class B [Member]
Net earnings	$ 20,745	$ 10,706
Less dividends declared	2,862	2,852
Undistributed earnings	$ 17,883	$ 7,854
Weighted-average shares outstanding, basic and diluted (in shares)	10,258	10,185
Net earnings per share, basic and diluted (in dollars per share)	$ 2.02	$ 1.05