Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from finance leases	$ 0.0	$ 0.1	$ 0.0	$ 0.1
Financing cash flows from finance leases	0.2	0.3	0.5	0.5
Operating cash flows from operating leases	4.2	3.6	7.9	7.1
Right-of-use assets obtained in exchange for new lease liabilities
Finance leases	0.0	0.1	0.0	0.1
Operating leases	$ 37.3	$ 3.6	$ 41.2	$ 12.1