Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020
Other Assets, Accrued Expenses and Other Liabilities [Abstract]
Receivables, net	$ 0.3	$ 0.4
Notes Receivable, Related Parties	3.8	4.8
Operating Lease, Right-of-Use Asset	5.0	3.6
Prepaid expenses	3.0	4.9
Land purchase contract deposits	10.0	5.5
Other assets	4.2	5.7
Total Other assets	26.3	24.9
Accrued employee compensation and benefits	2.8	6.2
Accrued property taxes	0.8	3.8
Operating Lease, Liability	5.3	3.8
Accrued interest	10.9	14.0
Contract liabilities	0.0	0.2
Deferred income	9.3	9.3
Taxes Payable	1.3	0.5
Accrued Development Costs	42.5	35.3
Other accrued expenses	3.8	10.2
Other liabilities	15.7	10.5
Total Accrued expenses and other liabilities	$ 92.4	$ 93.8