Leases (Details) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)
Lessee, Lease, Description [Line Items]
Sublease Income	$ 13.1	$ 13.1
Operating Lease, Weighted Average Remaining Lease Term	4 years 7 months 6 days	4 years 7 months 6 days
Operating Lease, Weighted Average Discount Rate, Percent	3.80%	3.80%
Operating Leases, Rent Expense	$ 8.0	$ 24.2
Operating Lease, Payments	$ 9.5	$ 27.4