Owned Inventory - Narrative (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2025 USD ($) lot home community	Sep. 30, 2024 USD ($) home	Sep. 30, 2023 USD ($)
Inventory Disclosure [Abstract]
Number of homes under construction | home	1,800	2,315
Number of homes under construction, spec homes | home	1,078	1,154
Total, spec homes	$ 417,400	$ 360,900
Number of homes under construction, in-process spec homes | home	577	827
In-process spec homes	$ 201,800	$ 231,400
Number of homes under construction, finished spec homes | home	501	327
Finished spec homes	$ 215,600	$ 129,500
Threshold number of homes below a minimum threshold of profitability | home	10
Number of projects in progress impaired (in community) | community	2
Total impairment charges on projects in progress	$ 8,642	0	$ 0
Number of land held for sale lots impaired (in lot) | lot	131
Total impairment charges on land held for sale	$ 2,733	0	0
Total abandonments charges	$ 1,584	$ 1,996	$ 641