Lease information Future minimum payments (Details) $ in Thousands	Jan. 31, 2017 USD ($)
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 2,199
Capital Lease Obligations, Current	231
Operating Leases, Future Minimum Payments, Due in Two Years	1,705
Capital Leases, Future Minimum Payments Due in Two Years	63
Operating Leases, Future Minimum Payments, Due in Three Years	1,536
Capital Leases, Future Minimum Payments Due in Three Years	1
Operating Leases, Future Minimum Payments, Due in Four Years	1,475
Capital Leases, Future Minimum Payments Due in Four Years	0
Operating Leases, Future Minimum Payments, Due in Five Years	1,477
Capital Leases, Future Minimum Payments Due in Five Years	0
Operating Leases, Future Minimum Payments, Due Thereafter	9,707
Capital Leases, Future Minimum Payments Due Thereafter	0
Operating Leases, Future Minimum Payments Due	18,099
Capital leases, future minimum payments, interest included in payments	295
Interest Portion of Minimum Lease Payments, Sale Leaseback Transactions	12
Capital Lease Obligations	$ 283