Inventory - Impairments and Lot Option Abandonment Charges, by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Real Estate, Write-down or Reserve [Line Items]
Impairment of Inventory, Projects in Progress	$ 0	$ 11,899	$ 0	$ 13,724
Impairment of inventory, land held for sale	470	18	564	586
Abandonments	0	0	188	788
Inventory impairments and abandonments	470	11,917	752	15,098
West Segment
Real Estate, Write-down or Reserve [Line Items]
Impairment of Inventory, Projects in Progress	0	5,216	0	6,729
Impairment of inventory, land held for sale	0	0	94	0
East Segment
Real Estate, Write-down or Reserve [Line Items]
Impairment of Inventory, Projects in Progress	0	5,894	0	5,894
Impairment of inventory, land held for sale	470	18	470	215
Abandonments	0	0	188	0
Southeast Segment
Real Estate, Write-down or Reserve [Line Items]
Impairment of inventory, land held for sale	0	0	0	371
Abandonments	0	0	0	788
Corporate and unallocated
Real Estate, Write-down or Reserve [Line Items]
Impairment of Inventory, Projects in Progress	$ 0	$ 789	$ 0	$ 1,101