Significant accounting policies Long lived assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Property, Plant and Equipment [Line Items]
Impairment of Tangible Assets, Other Descriptors	there was no impairment of long-lived assets
Depreciation and amortization	$ 5,336	$ 4,200
Land, buildings and improvements	22,330	14,758
Machinery and equipment	44,538	41,534
Furniture, office equipment and computer systems	4,704	5,632
Transportation equipment	3,690	40
Subtotal	75,262	61,964
Less accumulated depreciation and amortization	38,987	36,564
Property, plant and equipment, net of accumulated depreciation	$ 36,275	$ 25,400