Leases - Lease Cost and Other Information (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Finance Leases [Abstract]
Amortization of ROU assets	$ 2.0	$ 4.1
Interest on lease liabilities	0.5	1.0
Operating leases	7.9	16.3
Short-term lease cost	1.0	1.9
Variable lease cost	2.1	3.1
Total lease cost	$ 13.5	$ 26.4
Document Period End Date		Jun. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from finance leases		$ 2.0
Operating cash flows from operating leases		17.3
Financing cash flows from finance leases		3.7
Right-Of-Use Asset Obtained In Exchange For Lease Liability [Abstract]
ROU assets obtained in exchange for new finance lease liabilities		9.0
ROU assets obtained in exchange for new operating lease liabilities		$ 4.9
Finance leases
Remaining lease term (in years)	7 years 3 months 18 days	7 years 3 months 18 days
Discount rate	5.40%	5.40%
Operating leases
Remaining lease term (in years)	5 years	5 years
Discount rate	5.50%	5.50%