Inventory (Details) - Homebuilding [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Inventory [Line Items]
Carrying value of communities with impairment indicators	$ 201.9		$ 201.9
Impairment charges	5.2	$ 11.7	8.9	$ 23.6
Write-offs (recoveries) of earnest money deposits and pre-acquisition costs	$ 2.9	$ 3.7	$ 7.1	$ 10.4