Business Segments and Major Customer Information - Sales to countries outside the United States (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$ 394,677	$ 406,175	$ 381,511
All foreign [Member]
Segment Reporting Information [Line Items]
Net sales	45,893	49,254	38,909
Canada [Member]
Segment Reporting Information [Line Items]
Net sales	16,141	20,640	15,237
South America [Member]
Segment Reporting Information [Line Items]
Net sales	22,090	14,984	12,360
Other foreign sales [Member]
Segment Reporting Information [Line Items]
Net sales	7,662	13,630	11,312
United States [Member]
Segment Reporting Information [Line Items]
Net sales	$ 348,784	$ 356,921	$ 342,602