Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017
Other assets
Earnest money and refundable deposits	$ 522.7		$ 445.2
Insurance receivables	69.8		54.6	$ 56.0
Other receivables	107.5		81.7
Prepaid assets	33.9		36.9
Rental properties	35.1		39.2
Contract Asset Insurance Renewals	36.3		0.0
Other	84.6		55.3
Other assets	889.9		712.9
Accrued expenses and other liabilities
Reserves for legal claims	440.9		408.1	407.8		$ 420.6
Employee compensation and related liabilities	254.9		252.5
Warranty liability	229.0	$ 213.9	202.0	$ 176.4	$ 162.6	$ 143.7
Accrued interest	36.2		14.8
Federal and state income tax liabilities	52.2		35.2
Inventory related accruals	49.5		45.5
Customer deposits	67.4		58.1
Accrued property taxes	27.3		38.0
Other	120.1		73.3
Accrued expenses and other liabilities	1,277.5		1,127.5
Other Segments [Member]
Other assets
Other assets	40.2		0.9
Accrued expenses and other liabilities
Accrued expenses and other liabilities	$ 19.7		$ 9.9