Inventory - Impairments and Lot Option Abandonment Charges, by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Real Estate, Write-down or Reserve [Line Items]
Land Held for Sale	$ 38,588	$ 0	$ 38,588	$ 0
Total impairment and abandonment charges	147,611	0	148,618
Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Impairment charges on projects in progress	109,023	0	110,030	0
Discontinued Operations
Real Estate, Write-down or Reserve [Line Items]
Land Held for Sale	0	0	0	450
West Segment
Real Estate, Write-down or Reserve [Line Items]
Land Held for Sale	37,963	0	37,963	0
West Segment | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Impairment charges on projects in progress	92,912	0	92,912	0
Southeast Segment | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Impairment charges on projects in progress	0	0	858	0
Corporate and unallocated | Continuing Operations
Real Estate, Write-down or Reserve [Line Items]
Impairment charges on projects in progress	16,111	0	16,260	0
Land Held for Sale	$ 625	$ 0	$ 625	$ 0