COMPUTATION OF NET INCOME PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012	Oct. 31, 2011
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income	$ 1,825	$ 3,010	$ 4,628	$ 7,100
Less: Dividends declared	(1,060)	(1,120)	(3,247)	(3,001)
Allocation of undistributed net income	765	1,890	1,381	4,099
Net income per share [Abstract]
Dividends declared	1,060	1,120	3,247	3,001
Allocation of undistributed net income	765	1,890	1,381	4,099
Net income attributable to common stock	1,825	3,010	4,628	7,100
Common Class A [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income	1,503	2,499	3,822	5,888
Less: Dividends declared	(873)	(930)	(2,683)	(2,489)
Allocation of undistributed net income	630	1,569	1,139	3,399
Net income per share [Abstract]
Dividends declared	873	930	2,683	2,489
Allocation of undistributed net income	630	1,569	1,139	3,399
Net income attributable to common stock	1,503	2,499	3,822	5,888
Weighted average shares of common stock outstanding-basic (in shares)	12,561	12,975	12,634	12,892
Weighted average potential shares of common stock (in shares)	455	407	473	394
Weighted average shares of common stock and potential common shares outstanding-diluted (in shares)	13,016	13,382	13,107	13,286
Basic net income per common share (in dollars per share)	$ 0.12	$ 0.19	$ 0.30	$ 0.46
Diluted net income per common share (in dollars per share)	$ 0.12	$ 0.19	$ 0.29	$ 0.44
Antidilutive securities excluded from computation of earnings per share (in shares)	2,484,000	2,190,000	2,289,000	2,142,000
Common Class B [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income	322	511	806	1,212
Less: Dividends declared	(187)	(190)	(564)	(512)
Allocation of undistributed net income	135	321	242	700
Net income per share [Abstract]
Dividends declared	187	190	564	512
Allocation of undistributed net income	135	321	242	700
Net income attributable to common stock	$ 322	$ 511	$ 806	$ 1,212
Weighted average shares of common stock outstanding-basic (in shares)	3,157	3,203	3,163	3,194
Weighted average potential shares of common stock (in shares)	103	98	109	98
Weighted average shares of common stock and potential common shares outstanding-diluted (in shares)	3,260	3,301	3,272	3,292
Basic net income per common share (in dollars per share)	$ 0.10	$ 0.16	$ 0.25	$ 0.38
Diluted net income per common share (in dollars per share)	$ 0.10	$ 0.15	$ 0.25	$ 0.37
Antidilutive securities excluded from computation of earnings per share (in shares)	384,000	463,000	369,000	486,000