Commitments and Contingencies (Narrative) (Details) (USD $)	6 Months Ended
	Jan. 31, 2013	Jul. 31, 2012	Jan. 31, 2012
Holland Creek Metropolitan District [Member]
Credit-enhanced bonds issued amount	$ 8,000,000
Amount outstanding in letters of credit	8,100,000
Red Sky Ranch Metropolitan District [Member]
Other long-term liabilities	1,800,000	1,800,000	1,800,000
Estimated cessation date of capital improvement fee payment obligation	July 31, 2028
Various Other [Member]
Amount outstanding in letters of credit	59,500,000
Employee Housing Bonds [Member]
Amount outstanding in letters of credit	53,400,000
Workers' Compensation and General Liability Related to Construction and Development Activities [Member]
Amount outstanding in letters of credit	$ 4,500,000