Commitments and Contingencies (Details) - Homebuilding [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Changes in warranty liability
Warranty liability, beginning of period	$ 71.6	$ 57.3	$ 65.7	$ 56.9
Warranties issued	12.9	9.2	33.3	23.9
Changes in liability for pre-existing warranties	2.3	3.3	3.0	5.4
Settlements made	(9.4)	(8.5)	(24.6)	(24.9)
Warranty liability, end of period	$ 77.4	$ 61.3	$ 77.4	$ 61.3