Income Taxes - Schedule of Tax Attributes and Valuation Allowances (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Tax Benefit Amount
Non-United States capital loss carryforward	$ 10.8	$ 9.5
Net operating loss carryforwards	31.1	18.5
State tax credit carryforward	17.3	$ 16.5
Subtotal	59.2
Other deferred tax assets	34.2
Total	93.4
Valuation Allowance
Tax credit carryforward	34.2
Subtotal	23.8
Total	58.0
Non-United States
Tax Benefit Amount
Non-United States net operating loss carryforward	19.0
Non-United States net operating loss carryforward	4.9
Non-United States capital loss carryforward	10.8
Valuation Allowance
Net operating loss carryforward, subject to expiration	5.8
Non-United States net operating loss carryforward	4.0
Non-United States capital loss carryforward	10.8
United States
Tax Benefit Amount
Net operating loss carryforwards	0.3
State tax credit carryforward	1.1
Valuation Allowance
Net operating loss carryforward, subject to expiration	0.0
Tax credit carryforward	1.1
State and Local
Tax Benefit Amount
Net operating loss carryforwards	6.9
State tax credit carryforward	16.2
Valuation Allowance
Net operating loss carryforward, subject to expiration	1.4
Tax credit carryforward	$ 0.7