Income Taxes Income Taxes - Tax Reform (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Subsequent Event [Line Items]
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount		$ 11.2
Undistributed Earnings of Foreign Subsidiaries		$ 354.7
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate		24.53%	35.00%	35.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability		$ 8.6
Scenario, Forecast [Member]
Subsequent Event [Line Items]
Foreign Earnings Repatriated	$ 13.0