Other Assets, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Oct. 01, 2019	Sep. 30, 2019
Other Assets, Accrued Expenses and Other Liabilities [Abstract]
Accounts and Financing Receivable, after Allowance for Credit Loss	$ 0.4		$ 1.1
Notes Receivable, Related Parties	4.8		0.0
Operating Lease, Right-of-Use Asset	3.6	$ 2.7	0.0
Prepaid Expense	4.9		3.4
Deposits Assets	5.5		5.1
Other Assets, Miscellaneous	5.7		4.1
Other assets	24.9		13.7
Employee-related Liabilities	6.2		5.6
Accrual for Taxes Other than Income Taxes	3.8		2.1
Operating Lease, Liability	3.8	$ 2.9	0.0
Interest Payable	14.0		13.5
Contract with Customer, Liability, Current	0.2		2.5
Deferred Revenue	9.3		9.3
Taxes Payable	0.5		0.0
Accrued Development Costs	35.3		35.4
Other Accrued Liabilities	10.2		8.4
Other Liabilities	$ 10.5		$ 2.8
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent		us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent
Accrued expenses and other liabilities	$ 93.8		$ 79.6