Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2021 USD ($) home	Sep. 30, 2020 USD ($)	Sep. 30, 2019 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%
Income tax, refund claim			$ 4,600
Alternative minimum tax credit		$ 4,600	9,200
Income Tax Receivable, Alternative Minimum Tax		9,200
Income tax receivable	$ 9,929	9,252
Customer deposits	28,526	18,937
Contract with customer, liability, revenue recognized	18,100
Refunded by buyer	800
Advertising costs	$ 14,000	$ 15,900	$ 17,900
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)	1.00%