Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended			12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2016
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate					21.00%			24.50%
Undistributed Earnings of Foreign Subsidiaries	$ 351.6				$ 351.6	$ 354.7		$ 354.7
Foreign Earnings Repatriated					$ 13.0
Effective Income Tax Rate Reconciliation,Other Reconciling Items, Percent	0.10%	0.20%			0.10%		0.40%
Effective Income Tax Rate Reconciliation, Tax Settlement, State and Local, Amount	$ 0.7				$ 0.7
Effective Income Tax Rate Reconciliation, Tax Settlement, State and Local, Percent	3.00%						0.80%
Operating Loss Carryforwards	$ 9.4				9.4
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	5.7				5.7
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	6.5				6.5
Deferred Tax Assets, Valuation Allowance	3.5				3.5				$ 3.6
Income Tax Expense (Benefit)	$ 5.3	$ 8.9			$ 19.0		$ 41.2
Effective Income Tax Rate Reconciliation, Percent	25.00%	27.00%			25.00%		51.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount							$ 20.1
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent							25.00%
Deferred Income Tax Expense (Benefit)				$ 8.9		$ 0.3
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount			$ 0.7	$ 12.0