Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010	Jan. 31, 2011
Income Taxes (Textuals)
Income tax expense (benefit)	$ (6,171,000)	$ 81,566,000	$ 11,742,000	$ 72,196,000
Net operating loss carryforward					206,051,000
Net operating loss carryforwards expiration dates					Years ending January 31, 2024 through January 31, 2031
Charitable contribution deduction carryforward					37,273,000
General business credits carryovers expiring current year					41,000
Charitable contribution deduction carryforward expiring current year					6,068,000
General Business credits carryovers					19,070,000
Charitable contribution deduction carryforward expiration dates					Years ending January 31, 2012 through January 31, 2016
General Business credits carryovers expiration dates					Years ending January 31, 2012 through January 31, 2031
Alternative minimum tax carryforward					29,315,000
Net deferred tax asset unrecognized					$ 17,264,000