Lease information Property under capitalized leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Property, Plant and Equipment [Line Items]
Capital leases transportation equipment	$ 22	$ 22
Capital leased assets, gross	1,330	1,769
Capital leases other accumulated depreciation	646	726
Capital leases, net	684	1,043
Fixed assets acquired under capital leases	8	0
Other Capitalized Property Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Capital leases machinery and equipment	$ 1,308	$ 1,747