Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2022	Apr. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Other assets
Earnest money and refundable deposits	$ 1,685.7		$ 1,079.8
Mortgage hedging instruments and commitments	330.2		8.7
Other receivables	210.9		153.6
Insurance receivables	137.9		109.5
Prepaid assets	77.4		51.6
Contract assets - insurance agency commissions	74.3		58.6
Lease right of use assets	46.6		35.6
Mortgage servicing rights	10.6		4.1
Other	$ 52.4		$ 41.2
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total other assets		Total other assets
Total other assets	$ 2,960.3		$ 1,560.6
Accrued expenses and other liabilities
Reserves for legal claims	729.1		577.5	$ 473.8
Employee compensation and related liabilities	524.3		492.1
Warranty liability	454.3		376.3	$ 310.2
Inventory related accruals	403.6		261.2
Broker deposits related to hedging instruments	240.9		0.0
Customer deposits	224.2		193.4
Federal and state income tax liabilities	110.9		88.2
Accrued property taxes	60.1		51.0
Lease liabilities	47.9		37.0
Accrued interest	33.8		31.5
Mortgage hedging instruments and commitments	12.4		1.0
Other	$ 113.3		$ 100.4
Finance Lease, Right-of-Use Asset, Accumulated Amortization	Other Liabilities		Other Liabilities
Total accrued expenses and other liabilities	$ 3,138.3		$ 2,210.3
Vidler Water Resources, Inc.
Other assets
Business acquisition, intangible and other assets acquired	286.6	$ 280.1	0.0
Interest Rate Lock Commitments
Other assets
Interest rate lock commitments	47.7		17.9
Accrued expenses and other liabilities
Interest rate lock commitments	$ 183.5		$ 0.7