Other Assets, Accrued Expenses and Other Liabilities Detail - USD ($) $ in Millions	Mar. 31, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Receivables, net	$ 1.0	$ 1.1
Operating Lease, Right-of-Use Asset	2.7	0.0
Prepaid expenses	4.4	3.4
Land purchase contract deposits	6.9	5.1
Other assets	6.0	4.1
Total Other assets	21.0	13.7
Accrued employee compensation and benefits	6.7	5.6
Accrued property taxes	1.2	2.1
Accrued interest	14.3	13.5
Contract liabilities	3.1	2.5
Deferred income	9.4	9.3
Accrued Development Costs	27.0	35.4
Other accrued expenses	6.9	8.4
Other liabilities	3.5	2.8
Total Accrued expenses and other liabilities	75.0	79.6
Operating Lease, Liability	$ 2.9	$ 0.0