Lease information Future minimum payments (Details) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2013	Jan. 31, 2012
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 1,779
Capital Lease Obligations, Current	756
Operating Leases, Future Minimum Payments, Due in Two Years	1,428
Capital Leases, Future Minimum Payments Due in Two Years	703
Operating Leases, Future Minimum Payments, Due in Three Years	1,286
Capital Leases, Future Minimum Payments Due in Three Years	686
Operating Leases, Future Minimum Payments, Due in Four Years	1,247
Capital Leases, Future Minimum Payments Due in Four Years	659
Operating Leases, Future Minimum Payments, Due in Five Years	1,197
Capital Leases, Future Minimum Payments Due in Five Years	140
Operating Leases, Future Minimum Payments, Due Thereafter	2,712
Capital Leases, Future Minimum Payments Due Thereafter	0
Operating Leases, Future Minimum Payments Due	9,649
Capital Leases, Future Minimum Payments, Interest Included in Payments	2,944
Interest Portion of Minimum Lease Payments, Sale Leaseback Transactions	360
Capital Lease Obligations	$ 2,584	$ 1,831