Note 1 - Summary of Business and Significant Accounting Policies - Basic and Diluted Net (Loss) Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Net income (loss)	$ 4,936	$ 2,982	$ 1,113	$ 1,397	$ (5,172)	$ (161)	$ (1,161)	$ (2,571)	$ 10,428	$ (9,065)	$ (15,450)
Less: dividends declared									(5,479)	(5,367)	(5,301)
Undistributed net income (loss)									4,949	(14,432)	(20,751)
Dividends declared									5,479	5,367	5,301
Allocation of undistributed net income (loss)									4,949	(14,432)	(20,751)
Common Class A [Member]
Net income (loss)									8,939	(7,762)	(13,211)
Less: dividends declared									(4,696)	(4,596)	(4,531)
Undistributed net income (loss)									4,243	(12,358)	(17,742)
Dividends declared									4,696	4,596	4,531
Allocation of undistributed net income (loss)									$ 4,243	$ (12,358)	$ (17,742)
Weighted average shares of common stock outstanding—basic (in shares)									16,267	15,942	15,715
Weighted average potential shares of common stock (in shares)									1,585
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)									17,852	15,942	15,715
Basic net (loss) income per common share (in dollars per share)	$ 0.26	$ 0.16	$ 0.06	$ 0.07	$ (0.28)	$ (0.01)	$ (0.06)	$ (0.14)	$ 0.55	$ (0.49)	$ (0.84)
Diluted net (loss) income per common share (in dollars per share)	0.24	0.14	0.05	0.07	(0.28)	(0.01)	(0.06)	(0.14)	$ 0.50	$ (0.49)	$ (0.84)
Common Class B [Member]
Net income (loss)									$ 1,489	$ (1,303)	$ (2,239)
Less: dividends declared									(783)	(771)	(770)
Undistributed net income (loss)									706	(2,074)	(3,009)
Dividends declared									783	771	770
Allocation of undistributed net income (loss)									$ 706	$ (2,074)	$ (3,009)
Weighted average shares of common stock outstanding—basic (in shares)									3,256	3,213	3,206
Weighted average potential shares of common stock (in shares)									166
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)									3,422	3,213	3,206
Basic net (loss) income per common share (in dollars per share)	0.22	0.13	0.05	0.06	(0.23)	(0.01)	(0.05)	(0.12)	$ 0.46	$ (0.41)	$ (0.70)
Diluted net (loss) income per common share (in dollars per share)	$ 0.21	$ 0.12	$ 0.05	$ 0.06	$ (0.23)	$ (0.01)	$ (0.05)	$ (0.12)	$ 0.44	$ (0.41)	$ (0.70)