Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended				15 Months Ended	36 Months Ended
	Jun. 30, 2012 Home		Jun. 30, 2011		Jun. 30, 2012 Home		Jun. 30, 2011		Jun. 30, 2012 Home	Jun. 30, 2012 Home	Sep. 30, 2011
Income Taxes [Line Items]
Income tax expense (benefit)	$ (715.6)		$ 0.2		$ (712.5)		$ (57.8)
Cumulative three-year pre- tax income										26.1
Deferred tax assets	795.1				795.1				795.1	795.1	848.5
Valuation allowance	78.4				78.4				78.4	78.4	848.5
Valuation Allowance, Deferred Tax Asset, Change in Amount	716.7
Income (loss) before income taxes	72.2	[1]	28.9	[1]	143.7	[1]	(21.8)	[1]	206.4
Number of homes closed	4,957				13,315
Number of homes in backlog	7,311				7,311				7,311	7,311
Change in value of net sales orders	32.00%
Change in value of sales order backlog	40.00%				40.00%				40.00%	40.00%
Possible decrease in unrecognized tax benefits, including interest	3.3				3.3				3.3	3.3
Homebuilding [Member]
Income Taxes [Line Items]
Valuation allowance	78.4				78.4				78.4	78.4	848.5
Income (loss) before income taxes	58.3	[1]	22.2	[1]	118.0	[1]	(34.4)	[1]
Income taxes receivable	$ 12.9				$ 12.9				$ 12.9	$ 12.9	$ 12.4

[1] Expenses maintained at the corporate level consist primarily of interest and property taxes, which are capitalized and amortized to cost of sales or expensed directly, and the expenses related to operating the Company’s corporate office. The amortization of capitalized interest and property taxes is allocated to each segment based on the segment’s revenue, while interest expense and those expenses associated with the corporate office are allocated to each segment based on the segment’s inventory balances.