Inventory - Results of Discounted Cash Flow Analysis (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2018 USD ($) lot Community	Sep. 30, 2017 USD ($) lot Community	Sep. 30, 2016 USD ($) lot Community
Real Estate, Write-down or Reserve [Line Items]
Number of Communities Impaired | Community	1	1	3
Number of Lots Impaired | lot	25	46	291
Impairment Charge	$ 1,000	$ 1,693	$ 13,724
Estimated Fair Value of Impaired Inventory at time of Impairment	$ 1,312	$ 3,791	$ 34,418
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	$ 212	$ 68	$ 1,101
Estimated Fair Value of Impaired Inventory at time of Impairment	$ 0	$ 0	$ 0
Southeast | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of Communities Impaired | Community	1
Number of Lots Impaired | lot	25
Impairment Charge	$ 793
Estimated Fair Value of Impaired Inventory at time of Impairment	$ 1,312
West | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of Communities Impaired | Community			2
Number of Lots Impaired | lot			213
Impairment Charge			$ 6,729
Estimated Fair Value of Impaired Inventory at time of Impairment			$ 16,345
West | Operating Segments | 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
East | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Number of Communities Impaired | Community			1
Number of Lots Impaired | lot			78
Impairment Charge			$ 5,894
Estimated Fair Value of Impaired Inventory at time of Impairment			$ 18,073