Note 3 - Computation of Net Income (Loss) Per Share - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Net income (loss)	$ 3,213	$ 125	$ 2,863	$ (16,359)
Dividends declared	(1,451)	(1,426)	(4,330)	(4,187)
Undistributed net income (loss)	1,762	(1,301)	(1,467)	(20,546)
Dividends declared	1,451	1,426	4,330	4,187
Common Class A [Member]
Net income (loss)	2,770	107	2,470	(14,045)
Dividends declared	(1,251)	(1,226)	(3,732)	(3,596)
Undistributed net income (loss)	1,519	(1,119)	(1,262)	(17,641)
Dividends declared	$ 1,251	$ 1,226	$ 3,732	$ 3,596
Weighted average shares of common stock outstanding—basic (in shares)	17,367	16,918	17,242	16,586
Weighted average potential shares of common stock (in shares)	497	877	595	0
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)	17,864	17,795	17,837	16,586
Basic net loss per common share (in dollars per share)	$ 0.16	$ 0.01	$ 0.14	$ (0.85)
Diluted net loss per common share (in dollars per share)	0.16	0.01	0.14	(0.85)
Basic net (loss) income per share (in dollars per share)	0.16	0.01	0.14	(0.85)
Diluted net (loss) income per share (in dollars per share)	$ 0.16	$ 0.01	$ 0.14	$ (0.85)
Common Class B [Member]
Net income (loss)	$ 443	$ 18	$ 393	$ (2,314)
Dividends declared	(200)	(200)	(598)	(591)
Undistributed net income (loss)	243	(182)	(205)	(2,905)
Dividends declared	$ 200	$ 200	$ 598	$ 591
Weighted average shares of common stock outstanding—basic (in shares)	3,330	3,308	3,324	3,279
Weighted average potential shares of common stock (in shares)	57	90	65	0
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)	3,387	3,398	3,389	3,279
Basic net loss per common share (in dollars per share)	$ 0.13	$ 0.01	$ 0.12	$ (0.71)
Diluted net loss per common share (in dollars per share)	0.13	0.01	0.12	(0.71)
Basic net (loss) income per share (in dollars per share)	0.13	0.01	0.12	(0.71)
Diluted net (loss) income per share (in dollars per share)	$ 0.13	$ 0.01	$ 0.12	$ (0.71)