Other Assets and Accrued Expenses and Other Liabilities (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Sep. 30, 2010
Homebuilding other assets
Homebuilding other assets	$ 458.0		$ 449.4
Homebuilding [Member]
Homebuilding other assets
Insurance receivables	220.8		218.3
Earnest money and refundable deposits	65.4		59.1
Accounts and notes receivable	19.4		19.1
Prepaid assets	22.9		24.7
Other assets	83.6		77.2
Homebuilding other assets	412.1		398.4
Homebuilding accrued expenses and other liabilities
Construction defect and other litigation liabilities	539.9		529.6
Employee compensation and related liabilities	92.7		85.8
Warranty liability	48.8	48.9	46.2	41.0	43.8	46.2
Accrued interest	24.9		25.3
Federal and state income tax liabilities	23.3		22.5
Other liabilities	112.7		120.4
Homebuilding accrued expenses and other liabilities	$ 842.3		$ 829.8