Lease information Future minimum payments (Details) $ in Thousands	Jan. 31, 2016 USD ($)
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 1,944
Capital Lease Obligations, Current	1,386
Operating Leases, Future Minimum Payments, Due in Two Years	1,640
Capital Leases, Future Minimum Payments Due in Two Years	67
Operating Leases, Future Minimum Payments, Due in Three Years	1,378
Capital Leases, Future Minimum Payments Due in Three Years	0
Operating Leases, Future Minimum Payments, Due in Four Years	1,311
Capital Leases, Future Minimum Payments Due in Four Years	0
Operating Leases, Future Minimum Payments, Due in Five Years	1,327
Capital Leases, Future Minimum Payments Due in Five Years	0
Operating Leases, Future Minimum Payments, Due Thereafter	10,066
Capital Leases, Future Minimum Payments Due Thereafter	0
Operating Leases, Future Minimum Payments Due	17,666
Capital leases, future minimum payments, interest included in payments	1,453
Interest Portion of Minimum Lease Payments, Sale Leaseback Transactions	22
Capital Lease Obligations	$ 1,431