Fair Value (Detail) - Financial assets and liabilities measured at fair value on a recurring basis (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012		Jan. 31, 2012
Cash equivalents	$ 2		$ 2
Money market mutual fund (1)	320	[1]	620	[1]
Investment in cooperative (1)	219	[1]	219	[1]
Total assets	541		841
Interest rate swap derivative liabilities	3,532		4,235
Fair Value, Inputs, Level 1 [Member]
Cash equivalents	2		2
Money market mutual fund (1)	320	[1]	620	[1]
Investment in cooperative (1)		[1]		[1]
Total assets	322		622
Fair Value, Inputs, Level 2 [Member]
Money market mutual fund (1)		[1]		[1]
Investment in cooperative (1)		[1]		[1]
Interest rate swap derivative liabilities	3,532		4,235
Fair Value, Inputs, Level 3 [Member]
Money market mutual fund (1)		[1]		[1]
Investment in cooperative (1)	219	[1]	219	[1]
Total assets	$ 219		$ 219

[1] The money market mutual fund is included in "Restricted investments and deposits" and the investment in cooperative is included in "Other assets" on the accompanying Consolidated Condensed Balance Sheets.