Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Apr. 30, 2018	Jul. 31, 2017	Apr. 30, 2017
Amount outstanding in letters of credit	$ 63,300
Surety Bonds Outstanding	9,300
Holland Creek Metropolitan District [Member]
Credit-enhanced bonds issued amount	6,300
Amount outstanding in letters of credit	6,400
Red Sky Ranch Metropolitan District [Member]
Other long-term liabilities	$ 2,000	$ 2,000	$ 2,000
Estimated cessation date of capital improvement fee payment obligation	Jul. 31, 2031
Employee Housing Bonds [Member]
Amount outstanding in letters of credit	$ 53,400
Workers' Compensation and General Liability Related to Construction and Development Activities [Member]
Amount outstanding in letters of credit	$ 9,900