Notes and Accounts Receivable Net (Details Textual) (Stapleton advances [Member], USD $)	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Stapleton advances [Member]
Notes and Accounts Receivable, Net (Textual) [Abstract]
Interest Income Related to Infrastructure Advances to the Park Creek Metropolitan District	$ 6,439,000	$ 4,237,000	$ 3,120,000
Weighted Average Interest Rate of Infrastructure Advances to the Park Creek Metropolitan District	8.75%