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, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Net (loss) income	$ 125	$ 2,982	$ (16,359)	$ 5,492
Dividends declared	(1,426)	(1,374)	(4,187)	(4,105)
Undistributed net (loss) income	(1,301)	1,608	(20,546)	1,387
Net (loss) income per share
Dividends declared	1,426	1,374	4,187	4,105
Undistributed net (loss) income	(1,301)	1,608	(20,546)	1,387
Net (loss) income	125	2,982	(16,359)	5,492
Common Class A [Member]
Net (loss) income	107	2,557	(14,045)	4,707
Dividends declared	(1,226)	(1,178)	(3,596)	(3,518)
Undistributed net (loss) income	(1,119)	1,379	(17,641)	1,189
Net (loss) income per share
Dividends declared	1,226	1,178	3,596	3,518
Undistributed net (loss) income	(1,119)	1,379	(17,641)	1,189
Net (loss) income	$ 107	$ 2,557	$ (14,045)	$ 4,707
Weighted average shares of common stock outstanding—basic (in shares)	16,918	16,358	16,586	16,235
Weighted average potential shares of common stock (in shares)	877	1,590		1,676
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)	17,795	17,948	16,586	17,911
Basic net (loss) income per common share (in dollars per share)	$ 0.01	$ 0.16	$ (0.85)	$ 0.29
Diluted net (loss) income per common share (in dollars per share)	$ 0.01	$ 0.14	$ (0.85)	$ 0.26
Common Class B [Member]
Net (loss) income	$ 18	$ 425	$ (2,314)	$ 785
Dividends declared	(200)	(196)	(591)	(587)
Undistributed net (loss) income	(182)	229	(2,905)	198
Net (loss) income per share
Dividends declared	200	196	591	587
Undistributed net (loss) income	(182)	229	(2,905)	198
Net (loss) income	$ 18	$ 425	$ (2,314)	$ 785
Weighted average shares of common stock outstanding—basic (in shares)	3,308	3,264	3,279	3,253
Weighted average potential shares of common stock (in shares)	90	169		176
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)	3,398	3,433	3,279	3,429
Basic net (loss) income per common share (in dollars per share)	$ 0.01	$ 0.13	$ (0.71)	$ 0.24
Diluted net (loss) income per common share (in dollars per share)	$ 0.01	$ 0.12	$ (0.71)	$ 0.23