Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$ 13.7	$ 14.2
Operating cash flows for finance leases	2.7	2.9
Financing cash flows for finance leases	2.1	3.3
Assets obtained in exchange for lease obligations:
Operating leases	11.9	7.7
Finance leases	$ 0.0	$ 23.8