Inventory - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2016 USD ($) home Community	Jun. 30, 2015 Community	Jun. 30, 2016 USD ($) home Community	Sep. 30, 2015 USD ($) home
Real Estate Properties [Line Items]
Number of substantially completed homes unsold | home	172		172	128
Total value of substantially completed homes | $	$ 47.3		$ 47.3	$ 40.1
Threshold number of homes below a minimum threshold of profitability | home			10
Number of communities on watch list	3	0
Number of Communities Impaired	2		3
East Segment
Real Estate Properties [Line Items]
Number of communities on watch list	1
Number of Communities Impaired	1		1