Inventory Impairments and Land Option Cost Write-Offs (Details) (Homebuilding [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Sep. 30, 2013
Inventory Impairments and Land Option Cost Write Offs [Abstract]
Carrying value of communities with impairment indicators	$ 284.2		$ 284.2
Impairment charges	54.7	0	57.0	0
Write-offs (recoveries) of earnest money deposits and pre-acquisition costs	2.1	0.8	6.9	4.0
Land held for sale	18.9		18.9		34.0
Midwest [Member]
Inventory Impairments and Land Option Cost Write Offs [Abstract]
Impairment charges	$ 48.8	$ 0	$ 48.8	$ 0