Owned Inventory - Results of Discounted Cash Flow Analysis (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($) community lot
Real Estate, Write-down or Reserve [Line Items]
Impairment Charge	$ 109,000	$ 900	$ 1,700	$ 131,700
Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of communities impaired | community				10
Number of Lots Impaired | lot				854
Impairment Charge				$ 110,030
Estimated Fair Value of Impaired Inventory				$ 84,982
Corporate and unallocated | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of communities impaired | community				0
Number of Lots Impaired | lot				0
Impairment Charge				$ 16,260
Estimated Fair Value of Impaired Inventory				$ 14,166
West | Operating Segments | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of communities impaired | community				9
Number of Lots Impaired | lot				839
Impairment Charge				$ 92,912
Estimated Fair Value of Impaired Inventory				$ 69,449
Southeast | Operating Segments | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of communities impaired | community				1
Number of Lots Impaired | lot				15
Impairment Charge				$ 858
Estimated Fair Value of Impaired Inventory				$ 1,367