Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Other Assets, Accrued Expenses and Other Liabilities [Abstract]
Receivables, net	$ 0.4	$ 0.4
Earnest money notes receivable on sales contracts	0.7	4.8
Lease right of use assets	6.9	3.6
Prepaid expenses	15.4	4.9
Land purchase contract deposits	10.4	5.5
Other	$ 5.3	$ 5.7
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Other Assets	$ 39.1	$ 24.9
Accrued employee compensation and benefits	7.9	6.2
Accrued property taxes	3.4	3.8
Lease liabilities	7.3	3.8
Accrued interest	8.5	14.0
Contract liabilities	5.8	0.2
Deferred income	6.8	9.3
Income taxes payable	6.8	0.5
Other accrued expenses	8.9	10.2
Other liabilities	$ 1.3	$ 1.4
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other liabilities	Other liabilities
Accrued expenses and other liabilities	$ 56.7	$ 49.4