Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Sep. 30, 2025
Schedule of Other Assets, Accrued Expenses and Other Liabilities [Line Items]
Receivables, net	$ 19.5	$ 20.2
Lease right of use assets	15.9	13.7
Prepaid expenses	18.7	17.5
Land purchase contract deposits	34.1	34.5
Income taxes receivable	0.5	1.4
Other assets	$ 3.0	$ 3.3
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Other assets	$ 106.6	$ 104.6
Accrued employee compensation and benefits	5.9	16.9
Accrued property taxes	1.0	6.2
Lease liabilities	16.6	14.4
Accrued interest	14.4	2.5
Contract liabilities	0.5	0.7
Deferred income	4.1	4.1
Income taxes payable	14.9	11.9
Other accrued expenses	8.7	4.3
Other liabilities	$ 6.3	$ 8.1
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities
Accrued expenses and other liabilities	$ 87.3	$ 83.1
Bond Reimbursement Receivable	14.9	14.0
Bond Reimbursement Nonrecourse Liability	$ 14.9	$ 14.0