Retirement plans Cash flows (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 0
Defined Benefit Plan, Contributions by Plan Participants	0
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months		335
Defined Benefit Plan, Expected Future Benefit Payments, Year Two		348
Defined Benefit Plan, Expected Future Benefit Payments, Year Three		345
Defined Benefit Plan, Expected Future Benefit Payments, Year Four		366
Defined Benefit Plan, Expected Future Benefit Payments, Year Five		364
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter		$ 1,907