Land Held for Divestiture (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2011
Schedule of net gain loss on land held for divestiture [Abstract]
Sales of land held for divestiture	$ 34,510	$ 0	$ 34,510	$ 0
Cost of sales of land held for divestiture	(25,172)	0	(25,172)	0
Net gain on sales of land held for divestiture	9,338	0	9,338	0
Impairment of land held for divestiture	(15,796)	0	(15,796)	0
Net loss on land held for divestiture activites	$ (6,458)	$ 0	$ (6,458)	$ 0