Retirement plans Reconciliation of benefit obligations, plan assets and funded status (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Compensation and Retirement Disclosure [Abstract]
Defined benefit plan vested benefit obligation	$ 6,243	$ 6,650
Defined Benefit Plan, Accumulated Benefit Obligation	6,827	7,240
Defined Benefit Plan, Benefit Obligation	6,827	7,240	7,186
Service cost	78	171
Interest cost	293	299
Actuarial (gain) loss	(539)	(113)
Benefits paid	(245)	(303)
Defined Benefit Plan, Fair Value of Plan Assets	6,351	6,065	5,502
Defined Benefit Plan, Actual Return on Plan Assets	531	574
Defined Benefit Plan, Contributions by Employer	0	292
Unfunded status	(476)	(1,175)
Defined Benefit Plan, Current Assets	335	328
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent	1,038	1,304
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	(1,849)	(2,807)
Defined Benefit Plan, Amounts Recognized in Balance Sheet	(476)	(1,175)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	1,513	2,206
Unamortized prior service cost	0	273
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	$ 1,513	$ 2,479