Inventory Impairments and Land Option Cost Write-Offs (Details) (Homebuilding [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Sep. 30, 2013
Inventory Impairments and Land Option Cost Write Offs [Abstract]
Carrying value of communities with impairment indicators	$ 173.4		$ 173.4
Impairment charges	2.3	0	2.3	0
Write-offs (recoveries) of earnest money deposits and pre-acquisition costs	2.1	1.8	4.8	3.2
Land held for sale	23.4		23.4		34.0
Southeast [Member]
Inventory Impairments and Land Option Cost Write Offs [Abstract]
Impairment charges	2.1
West [Member]
Inventory Impairments and Land Option Cost Write Offs [Abstract]
Impairment charges	$ 0.2