Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Sep. 30, 2015 USD ($) home	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)
Summary of Significant Accounting Policies [Line Items]
Threshold Number of Homes Below a Minimum Threshold of Profitability | home	10
Measurement threshold of likelihood of being realized (percent)	50.00%
Advertising costs	$ 18.0	$ 17.8	$ 14.2
Minimum
Summary of Significant Accounting Policies [Line Items]
Time to Develop, Sell, Construct and Close All Houses	3 years
Estimated future warranty costs as a percentage or revenue (percent)	0.26011%
Maximum
Summary of Significant Accounting Policies [Line Items]
Time to Develop, Sell, Construct and Close All Houses	5 years
Estimated future warranty costs as a percentage or revenue (percent)	2.61%
Buildings | Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life	25 years
Buildings | Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life	30 years
Information systems | Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life	5 years
Furniture, Fixtures, Computer and Office Equipment | Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life	3 years
Furniture, Fixtures, Computer and Office Equipment | Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life	7 years