Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2025 USD ($) home	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Summary of Significant Accounting Policies [Line Items]
Threshold number of homes below a minimum threshold of profitability | home	10
Measurement threshold of likelihood of being realized (percent)	50.00%
Customer deposits	$ 14,260	$ 18,669
Contract with customer, liability, revenue recognized	16,100
Refunded by buyer	1,900
Advertising costs	$ 23,000	$ 19,900	$ 15,100
Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated time to develop, sell, construct and close all homes (in years)	3 years
Estimated future warranty costs as a percentage or revenue (percent)	0.30%
Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated time to develop, sell, construct and close all homes (in years)	5 years
Estimated future warranty costs as a percentage or revenue (percent)	0.90%