Inventory - Narrative (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2017 USD ($) home Community	Sep. 30, 2017 USD ($) home lot Community	Sep. 30, 2017 USD ($) home Community	Sep. 30, 2017 USD ($) home Community	Sep. 30, 2016 USD ($) home Community	Sep. 30, 2015 Community
Real Estate [Abstract]
Number of substantially completed homes not subject to a sales contract | home	171	171	171	171	178
Total value of substantially completed homes | $	$ 52,600	$ 52,600	$ 52,600	$ 52,600	$ 56,100
Threshold number of homes below a minimum threshold of profitability	10	10
Number of watch list communities requiring further analysis | Community	2	2	2	2	7	0
Impairment charge | $				$ 1,693	$ 13,724
Number of Communities Impaired | Community			1		3