Leases (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Operating right of use assets	$ 75.0	$ 75.0	$ 0.0
Operating Lease, Cost	$ 4.1	$ 11.1
Operating Lease, Weighted Average Remaining Lease Term	11 years 7 months 20 days	11 years 7 months 20 days
Operating Lease, Weighted Average Discount Rate, Percent	3.90%	3.90%
Operating Lease, Payments	$ 2.9	$ 8.4
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	46.0	81.0
Operating lease liabilities	$ 87.4	$ 87.4	$ 0.0