Investments and Restricted Deposits (Detail) - Schedule of Financial information For Equity Method Investment (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Patriot [Member]
Net sales and revenue	$ 94,093	$ 89,812
Gross profit	5,142	1,777
Income from continuing operations	3,599	(436)
Net income	3,599	(436)
Big River [Member]
Net sales and revenue	294,628	291,003
Gross profit	15,619	14,008
Income from continuing operations	6,632	5,718
Net income	$ 6,632	$ 5,718