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, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Net income (loss)	$ 2,982	$ (161)	$ 5,492	$ (3,893)
Dividends declared	(1,374)	(1,345)	(4,105)	(4,021)
Undistributed net income (loss)	1,608	(1,506)	1,387	(7,914)
Dividends declared	1,374	1,345	4,105	4,021
Net income	2,982	(161)	5,492	(3,893)
Common Class A [Member]
Net income (loss)	2,557	(139)	4,707	(3,332)
Dividends declared	(1,178)	(1,152)	(3,518)	(3,442)
Undistributed net income (loss)	1,379	(1,291)	1,189	(6,774)
Dividends declared	1,178	1,152	3,518	3,442
Net income	$ 2,557	$ (139)	$ 4,707	$ (3,332)
Weighted average shares of common stock outstanding—basic (in shares)	16,358	16,011	16,235	15,913
Weighted average potential shares of common stock (in shares)	1,590		1,676
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)	17,948	16,011	17,911	15,913
Basic income per share (in dollars per share)	$ 0.16	$ (0.01)	$ 0.29	$ (0.21)
Diluted income per share (in dollars per share)	$ 0.14	$ (0.01)	$ 0.26	$ (0.21)
Common Class B [Member]
Net income (loss)	$ 425	$ (22)	$ 785	$ (561)
Dividends declared	(196)	(193)	(587)	(579)
Undistributed net income (loss)	229	(215)	198	(1,140)
Dividends declared	196	193	587	579
Net income	$ 425	$ (22)	$ 785	$ (561)
Weighted average shares of common stock outstanding—basic (in shares)	3,264	3,214	3,253	3,212
Weighted average potential shares of common stock (in shares)	169		176
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)	3,433	3,214	3,429	3,212
Basic income per share (in dollars per share)	$ 0.13	$ (0.01)	$ 0.24	$ (0.17)
Diluted income per share (in dollars per share)	$ 0.12	$ (0.01)	$ 0.23	$ (0.17)