Segment Information (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2011	Jan. 31, 2012
Geographic Segment Data
Net sales	$ 118,027	$ 113,231	$ 221,682	$ 203,085
Operating Income	10,749	5,014	19,237	6,594
Total Assets	479,474	495,973	479,474	495,973	506,043
Long-Lived Assets	32,333	37,308	32,333	37,308	36,290
United States [Member]
Geographic Segment Data
Net sales	59,887	54,874	110,801	100,096
Operating Income	(2,451)	(4,774)	(7,502)	(8,651)
Total Assets	196,256	185,174	196,256	185,174	213,363
Long-Lived Assets	26,477	29,076	26,477	29,076	28,476
International [Member]
Geographic Segment Data
Net sales	58,140	58,357	110,881	102,989
Operating Income	13,200	9,788	26,739	15,245
Total Assets	283,218	310,799	283,218	310,799	292,680
Long-Lived Assets	$ 5,856	$ 8,232	$ 5,856	$ 8,232	$ 7,814