Leases - Summary of Components of Lease Expense (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lease cost
Operating lease cost	$ 2.7	$ 7.2
Short-term lease cost	6.7	22.4
Variable lease cost	1.3	5.1
Finance lease cost
Amortization of right-of-use assets	3.4	9.7
Interest expense	0.4	1.2
Total lease cost	$ 14.5	$ 45.6