Segment Information (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Jan. 31, 2014
Geographic segment data
Net sales	$ 120,921	$ 110,010
Operating (Loss) / Income	10,921	10,005
Total Assets	574,884	515,379	578,610
Property, plant and equipment, net	46,806	46,289	47,796
United States
Geographic segment data
Net sales	62,279	58,477
Operating (Loss) / Income	(843)	2,435
Total Assets	218,760	195,836	239,890
Property, plant and equipment, net	24,969	25,938	25,943
International
Geographic segment data
Net sales	58,642	51,533
Operating (Loss) / Income	11,764	7,570
Total Assets	356,124	319,543	338,720
Property, plant and equipment, net	$ 21,837	$ 20,351	$ 21,853