Owned Inventory - Narrative (Details)	3 Months Ended
	Dec. 31, 2021 USD ($) home	Dec. 31, 2020 USD ($) home
Inventory Disclosure [Abstract]
Number of homes under construction | home	3,196	2,912
Number of homes under construction, spec homes | home	744	576
Total, spec homes | $	$ 150,800,000	$ 116,400,000
Number of homes under Construction, in-process spec homes | home	711	542
In-process spec homes | $	$ 139,500,000	$ 105,200,000
Number of homes under construction, finished spec homes | home	33	34
Finished spec homes | $	$ 11,300,000	$ 11,200,000
Threshold number of homes below a minimum threshold of profitability | home	10
Impairment charges on land held for sale | $	$ 0	0
Abandonment charges | $	$ 0	$ 500,000