Inventory Impairments and Land Option Cost Write-Offs (Details) (Homebuilding [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Homebuilding [Member]
Inventory Impairments Information [Line Items]
Carrying value of communities with impairment indicators	$ 165.9	$ 165.9
Carrying value of communities impaired	32.6	32.6
Impairment charges	21.3	21.3	3.2	37.3
Write-offs (recoveries) of earnest money deposits and pre-acquisition costs		9.8	3.0	8.1
Land held for sale	$ 34.0	$ 34.0	$ 32.6