Lease information Property under capitalized leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Property, Plant and Equipment [Line Items]
Capital leases transportation equipment	$ 9	$ 22
Capital leased assets, gross	1,738	1,330
Capital leases other accumulated depreciation	699	646
Capital leases, net	1,039	684
Fixed assets acquired under capital leases	841	8
Other Capitalized Property Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Capital leases machinery and equipment	$ 1,729	$ 1,308