Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Real Estate Inventory, Capitalized Interest Costs [Roll Forward]
Capitalized interest in inventory, beginning of period	$ 138,108	$ 123,457	$ 87,619
Interest incurred	105,551	119,360	121,754
Capitalized interest impaired	(56)	(710)	0
Interest expense not qualified for capitalization and included as other expense	(15,636)	(25,388)	(29,752)
Capitalized interest amortized to home construction and land sales expenses	(88,764)	(78,611)	(56,164)
Capitalized interest in inventory, end of period	$ 139,203	$ 138,108	$ 123,457