Inventory - Impairments and Lot Option Abandonment Charges, by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Real Estate, Write-down or Reserve [Line Items]
Total impairment and abandonment charges	$ 0	$ 282	$ 0	$ 282
Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Total impairment and abandonment charges	0	282	0	282
Discontinued Operations
Real Estate, Write-down or Reserve [Line Items]
Land Held for Sale	0	0	450	0
Total impairment and abandonment charges	0	0	450	0
West Segment
Real Estate, Write-down or Reserve [Line Items]
Land Held for Sale	0	94	0	94
East Segment
Real Estate, Write-down or Reserve [Line Items]
Abandonments	$ 0	$ 188	$ 0	$ 188