Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017
Other assets
Earnest money and refundable deposits	$ 477.0		$ 445.2
Insurance receivables	56.9		54.6	$ 69.0
Other receivables	79.4		81.7
Prepaid assets	30.9		36.9
Rental properties	33.9		39.2
Contract Asset Insurance Renewals	34.4		0.0
Other	73.2		55.3
Other assets	785.7		712.9
Accrued expenses and other liabilities
Reserves for legal claims	419.1		408.1	443.6		$ 420.6
Employee compensation and related liabilities	244.5		252.5
Warranty liability	213.9	$ 205.6	202.0	$ 162.6	$ 149.4	$ 143.7
Accrued interest	12.9		14.8
Federal and state income tax liabilities	83.8		35.2
Inventory related accruals	42.6		45.5
Customer deposits	62.5		58.1
Accrued property taxes	20.5		38.0
Other	92.3		73.3
Accrued expenses and other liabilities	1,192.1		1,127.5
Other Segments [Member]
Other assets
Other assets	37.4		0.9
Accrued expenses and other liabilities
Accrued expenses and other liabilities	$ 10.9		$ 9.9