Interest - Schedule of Capitalized Interest (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Real Estate Inventory, Capitalized Interest Costs [Roll Forward]
Capitalized interest in inventory, beginning of period	$ 144,847	$ 144,299	$ 139,203	$ 138,108
Interest incurred	25,492	26,482	51,047	53,569
Interest expense not qualified for capitalization and included as other expense	(1,650)	(4,046)	(5,085)	(9,298)
Capitalized interest amortized to home construction and land sales expenses	(19,655)	(19,819)	(36,131)	(35,463)
Capitalized interest in inventory, end of period	$ 149,034	$ 146,916	$ 149,034	$ 146,916