Leases - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lease Cost
Operating lease costs	$ 15.7	$ 13.5
Short-term lease costs (1)	7.6	3.6
Sublease income	(1.9)	(1.7)
Net lease costs	21.4	15.4
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	(15.7)	(13.5)
Non-cash lease liability arising from obtaining right of use assets during the period	$ 6.8	$ 0.0
Weighted-average remaining lease term (years) operating leases	6 years 7 months 6 days
Weighted-average discount rate operating leases (2)	6.00%