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, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Net (loss) income	$ (15,159)	$ 1,533	$ 968	$ (2,792)	$ 4,146	$ 2,586	$ 1,631	$ 549	$ (15,450)	$ 8,912	$ 12,946
Less: dividends declared									(5,301)	(5,235)	(4,452)
Undistributed net (loss) income									(20,751)	3,677	8,494
Dividends declared									5,301	5,235	4,452
Allocation of undistributed net (loss) income									(20,751)	3,677	8,494
Common Class A [Member]
Net (loss) income									(13,211)	7,606	10,729
Less: dividends declared									(4,531)	(4,466)	(3,688)
Undistributed net (loss) income									(17,742)	3,140	7,041
Dividends declared									4,531	4,466	3,688
Allocation of undistributed net (loss) income									$ (17,742)	$ 3,140	$ 7,041
Weighted average shares of common stock outstanding—basic (in shares)									15,715	15,466	12,841
Weighted average potential shares of common stock (in shares)										758	712
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)									15,715	16,224	13,553
Basic net (loss) income per common share (in dollars per share)	$ (0.82)	$ 0.08	$ 0.05	$ (0.15)	$ 0.23	$ 0.14	$ 0.09	$ 0.03	$ (0.84)	$ 0.49	$ 0.84
Diluted net (loss) income per common share (in dollars per share)	(0.82)	0.08	0.05	(0.15)	0.22	0.14	0.09	0.03	$ (0.84)	$ 0.47	$ 0.79
Common Class B [Member]
Net (loss) income									$ (2,239)	$ 1,306	$ 2,217
Less: dividends declared									(770)	(769)	(764)
Undistributed net (loss) income									(3,009)	537	1,453
Dividends declared									770	769	764
Allocation of undistributed net (loss) income									$ (3,009)	$ 537	$ 1,453
Weighted average shares of common stock outstanding—basic (in shares)									3,206	3,201	3,183
Weighted average potential shares of common stock (in shares)										82	88
Weighted average shares of common stock and potential common shares outstanding—diluted (in shares)									3,206	3,283	3,271
Basic net (loss) income per common share (in dollars per share)	(0.68)	0.07	0.04	(0.13)	0.19	0.12	0.08	0.03	$ (0.70)	$ 0.41	$ 0.70
Diluted net (loss) income per common share (in dollars per share)	$ (0.68)	$ 0.07	$ 0.04	$ (0.13)	$ 0.18	$ 0.12	$ 0.07	$ 0.02	$ (0.70)	$ 0.40	$ 0.68