Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$ 4.7	$ 6.8	$ 17.6	$ 26.4
Operating cash flows for finance leases	1.1	0.1	2.9	0.5
Financing cash flows for finance leases	2.8	0.2	5.6	8.1
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	0.0	0.2	6.8	2.3
Finance leases	$ 1.1	$ 0.5	$ 21.3	$ 1.5