Income Taxes - Additional Disclosures (Details) $ in Millions	12 Months Ended
	Sep. 30, 2019 USD ($)
Operating Loss Carryforwards [Line Items]
Increase (decrease) to the valuation allowance	$ 3.3
Undistributed losses of foreign subsidiaries	61.0
Undistributed earnings of foreign subsidiaries, estimated taxes recognized upon distribution	3.4
State Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	120.0
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	50.2
Tax credit carryforward	2.6
Capital Loss Carryforward
Operating Loss Carryforwards [Line Items]
Increase (decrease) to the valuation allowance	$ (3.0)