Inventory Inventory - Quantitative Unobservable Inputs (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2016 USD ($) home	Sep. 30, 2014 USD ($) home
Quantitative unobservable inputs for inventory impairment [Line Items]
Discount rate		14.97%
Minimum
Quantitative unobservable inputs for inventory impairment [Line Items]
Average selling price (in thousands) (a) | $	$ 355	$ 260
Closings per community per month | home	2	1
Discount rate	14.15%
Maximum
Quantitative unobservable inputs for inventory impairment [Line Items]
Average selling price (in thousands) (a) | $	$ 560	$ 280
Closings per community per month | home	4	4
Discount rate	15.33%