Leases - As a Lessee - Supplemental Cash Flow (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 5.6	$ 5.1
Operating cash flows from finance leases	0.4	0.5
Financing cash flows from finance leases	0.7	0.6
Non-cash right-of-use assets obtained in exchange for lease liabilities:
Operating leases	50.6	87.0
Finance leases	$ 0.0	$ 0.0