Deferred and restricted stock (Details) - USD ($)	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Restricted stock [Line Items]
Deferred compensation liabilities	$ 529,000	$ 495,000
Restricted stock grants	254,000	108,000
Restricted stock granted, weighted average grant price	$ 7.29	$ 6.38
Restricted stock issued	(91,000)	(26,000)
Restricted stock forfeited	(36,000)	(5,000)
Restricted stock, forfeitures, weighted average grant price	$ 7.75	$ 6.38
Deferred shares outstanding		163,000	86,000
Restricted stock, outstanding, weighted average grant price	$ 8.75	$ 6.40	$ 14.52
Restricted stock, aggregate intrinsic value	$ 2,540,000	$ 1,040,000	$ 1,242,000
Unrecognized restricted stock expense	$ 200,000
Cost is expected to be recognized over the weighted-average period	2 years
Director [Member]
Restricted stock [Line Items]
Deferred shares granted value	$ 40,000
Deferred Compensation, Share-based Payments [Member]
Restricted stock [Line Items]
Deferred shares outstanding	60,495
Restricted Stock [Member]
Restricted stock [Line Items]
Deferred shares outstanding	290,000
Vesting period restricted stock	3 years
Unrecognized restricted stock expense	$ 1,200,000
Cost is expected to be recognized over the weighted-average period	2 years 2 months