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 for operating leases	$ 4.7	$ 6.8	$ 12.9	$ 19.6
Operating cash flows for finance leases	1.2	0.1	1.9	0.3
Financing cash flows for finance leases	1.5	2.1	2.8	7.9
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	3.7	0.8	6.8	2.1
Finance leases	$ 16.7	$ 0.8	$ 20.3	$ 0.9