Interest - Schedule of Capitalized Interest (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Real Estate Inventory, Capitalized Interest Costs [Roll Forward]
Capitalized interest in inventory, beginning of period	$ 119,148	$ 137,010	$ 119,659	$ 136,565
Interest incurred	19,345	22,271	39,247	43,827
Interest expense not qualified for capitalization and included as other expense	(969)	(1,928)	(2,569)	(3,370)
Capitalized interest amortized to home construction and land sales expenses	(24,110)	(22,660)	(42,923)	(42,329)
Capitalized interest in inventory, end of period	$ 113,414	$ 134,693	$ 113,414	$ 134,693