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, 2019	Dec. 31, 2018
Net (loss) earnings	$ (8,743)	$ 20,709
Undistributed (loss) earnings	(12,095)	17,391
Common Class A [Member]
Net (loss) earnings	(1,531)	3,521
Less dividends declared	518	522
Undistributed (loss) earnings	$ (2,049)	$ 2,999
Weighted-average shares outstanding, basic and diluted (in shares)	2,167	2,175
Net earnings per share, basic and diluted (in dollars per share)	$ (0.71)	$ 1.62
Common Class B [Member]
Net (loss) earnings	$ (7,212)	$ 17,188
Less dividends declared	2,834	2,796
Undistributed (loss) earnings	$ (10,046)	$ 14,392
Weighted-average shares outstanding, basic and diluted (in shares)	10,117	9,939
Net earnings per share, basic and diluted (in dollars per share)	$ (0.71)	$ 1.73