Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($) home	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($) lot	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Oct. 01, 2019 USD ($)
Summary of Significant Accounting Policies [Line Items]
Threshold number of homes below a minimum threshold of profitability			10		10
Measurement threshold of likelihood of being realized (percent)				50.00%
Federal and state tax carryforwards	$ 192,981	$ 192,981	$ 192,981	$ 192,981	$ 192,981	$ 208,360
Alternative minimum tax credit						4,600
Customer deposits	18,937	18,937	18,937	18,937	18,937	11,539
Contract with customer, liability, revenue recognized		10,500
Refunded by buyer		1,000
Advertising costs		15,900				17,900	$ 17,600
Operating lease right-of-use assets	13,103	13,103	13,103	13,103	13,103	0
Operating lease liabilities	15,333	15,333	15,333	15,333	15,333	$ 0
Accounting Standards Update 2016-02
Summary of Significant Accounting Policies [Line Items]
Operating lease right-of-use assets	13,895	13,895	13,895	13,895	13,895			$ 13,900
Operating lease liabilities	$ 16,028	$ 16,028	$ 16,028	$ 16,028	$ 16,028			$ 16,000
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)				1.30%