Inventory - Results of Discounted Cash Flow Analysis (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2019 USD ($) lot Community	Sep. 30, 2018 USD ($) lot Community	Sep. 30, 2017 USD ($) lot Community
Real Estate, Write-down or Reserve [Line Items]
Number of communities impaired | Community	10	1	1
Number of Lots Impaired | lot	854	25	46
Impairment Charge	$ 110,030	$ 1,005	$ 1,693
Estimated Fair Value of Impaired Inventory at Time of Impairment	$ 84,982	$ 1,312	$ 3,791
Corporate and unallocated | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of communities impaired | Community	0	0	0
Number of Lots Impaired | lot	0	0	0
Impairment Charge	$ 16,260	$ 212	$ 68
Estimated Fair Value of Impaired Inventory at Time of Impairment	$ 14,166	$ 0	$ 0
West | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of communities impaired | Community			1
Number of Lots Impaired | lot			46
Impairment Charge			$ 1,625
Estimated Fair Value of Impaired Inventory at Time of Impairment			$ 3,791
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 at Time of Impairment	$ 69,449
Southeast | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of communities impaired | Community	1	1
Number of Lots Impaired | lot	15	25
Impairment Charge	$ 858	$ 793
Estimated Fair Value of Impaired Inventory at Time of Impairment	$ 1,367	$ 1,312