Owned Inventory - Narrative (Details)	3 Months Ended
	Dec. 31, 2023 USD ($) home	Dec. 31, 2022 USD ($)	Sep. 30, 2023 USD ($) home
Inventory Disclosure [Abstract]
Number of homes under construction | home	2,495		2,163
Number of homes under construction, spec homes | home	982		779
Total, spec homes	$ 292,400,000		$ 218,000,000
Number of homes under construction, in-process spec homes | home	789		645
In-process spec homes	$ 211,700,000		$ 162,000,000
Number of homes under construction, finished spec homes | home	193		134
Finished spec homes	$ 80,700,000		$ 56,000,000
Threshold number of homes below a minimum threshold of profitability | home	10
Impairment of projects in process	$ 0	$ 0
Total impairment charges on land held for sale	0	0
Total abandonments charges	$ 0	$ 190,000