Inventory - Impairments and Lot Option Abandonment Charges, by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Real Estate, Write-down or Reserve [Line Items]
Impairment of Inventory, Projects in Progress	$ 0	$ 1,825	$ 0	$ 1,825
Impairment of inventory, land held for sale	94	0	94	568
Abandonments	188	0	188	788
Total impairment and abandonment charges	282	1,825	282	3,181
West Segment
Real Estate, Write-down or Reserve [Line Items]
Impairment of Inventory, Projects in Progress	0	1,513	0	1,513
Impairment of inventory, land held for sale	94	0	94	0
East Segment
Real Estate, Write-down or Reserve [Line Items]
Impairment of inventory, land held for sale	0	0	0	197
Abandonments	188	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	$ 312	$ 0	$ 312