Leases - Lease Costs (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Operating Lease Cost
Fixed lease cost	$ 9.3
Short-term lease cost	10.1
Variable lease cost	4.2
Finance Lease Cost
Amortization of leased assets	1.3
Interest on leased liabilities	1.9
Variable lease cost	1.3
Total lease cost	$ 28.1